Term pack

Class 10 Science

Name: ________________________

Skills in this pack

Chemical reactions and equations
Acids, bases and salts
Metals, non-metals and the reactivity series
Carbon and its compounds
Life processes
Control and coordination
How organisms reproduce
Heredity
Reflection and refraction of light
The human eye and the colourful world
Electricity
Magnetic effects of electric current

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Class 10 Science · 1 of 12

Chemical reactions and equations

Balance a skeletal equation by counting atoms, name the five kinds of reaction the chapter sets out, and say which substance has been oxidised and which reduced.

1.Bags of crisps are flushed with nitrogen before they are sealed. What is that for?
- a) It keeps the crisps dry
- b) It cools the crisps down
- c) It stops the bag from being crushed
- d) It keeps the fat in them from being oxidised
2.Iron nails are left in blue copper sulphate solution for twenty minutes. What do you see when they come out?
- a) The nails have turned black and the solution is clear
- b) The nails are unchanged and the blue is deeper
- c) The nails have turned brownish and the blue has faded
- d) The nails have dissolved and the solution is green
3.Limestone is heated strongly in a kiln and gives quick lime and carbon dioxide. What kind of reaction is that?
- a) A precipitation reaction
- b) A combination reaction
- c) A displacement reaction
- d) Thermal decomposition
4.Zinc granules are dropped into dilute sulphuric acid. Bubbles rise round them and the tube grows warm. Which two of the chapter's signs of a reaction is that?
- a) The colour changes, and a gas is given off
- b) The temperature changes, and the colour changes
- c) The state changes, and the colour changes
- d) A gas is given off, and the temperature changes
5.Match each everyday sight to what it is called.
- An iron gate turning reddish brown
- A silver spoon going black
- Butter left out until it smells off
- A white solid appearing as two clear solutions meet
- Rusting
- Corrosion
- Precipitation
- Rancidity
6.Put the chapter's balancing procedure back into the order it gives, starting with "Draw a box round each formula, and change nothing inside a box".
- Draw a box round each formula, and change nothing inside a box
- Balance the elements that are still unequal, one at a time
- Count the atoms on both sides again to check the equation
- Start with the compound that has the most atoms, and balance its commonest element
- Write in the physical states of the reactants and products
- List how many atoms of each element sit on the two sides
7.In 2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂, how many oxygen atoms stand on the right-hand side? Answer with a number.
8.Sort each of these by whether energy comes out of the reaction or goes into it.
Groups: Heat given out · Energy taken in
- Natural gas burning
- Respiration in our cells
- Quick lime added to water
- Silver chloride left in sunlight
- Water split by an electric current
- Green crystals heated until they give off a sharp smell

Chemical reactions and equations · Class 10 Science · www.arenapublications.com/learn

Class 10 Science · 2 of 12

Acids, bases and salts

Predict what an acid gives with a metal, a carbonate and a base, read a solution's nature off the pH scale, and name the salts that common salt is turned into.

1.Blue copper sulphate crystals are heated until they turn white, and droplets of water collect in the tube. How many water molecules does one formula unit of the hydrated salt hold? Answer with a number.
2.Match each natural source to the acid the chapter names in it.
- Vinegar
- Lemon
- Tamarind
- Tomato
- Curd
- An ant sting
- Oxalic acid
- Acetic acid
- Lactic acid
- Tartaric acid
- Methanoic acid
- Citric acid
3.Bleaching powder is made from chlorine and one other substance. Which?
- a) Common salt
- b) Washing soda
- c) Plaster of Paris
- d) Dry slaked lime
4.Common salt is turned into bleaching powder in stages. Put them in order, beginning with "Brine, common salt dissolved in water".
- Bleaching powder
- Chlorine given off at the anode
- An electric current passed through the brine
- Chlorine acting on dry slaked lime
- Brine, common salt dissolved in water
5.Sort each of these by whether the chapter treats it as acidic or as basic.
Groups: Acidic · Basic
- Milk of magnesia
- The sting left by a bee
- Toothpaste
- Gastric juice in the stomach
- A solution of baking soda
- The stinging hair of a nettle leaf
6.A strip of pH paper scale is drawn below, running from 0 at the left to 14 at the right. Tap the stretch a basic solution would read in.
Write the number of the part.
7.Baking powder is baking soda mixed with tartaric acid. What makes a cake rise when the powder is heated?
- a) Steam given off by the tartaric acid
- b) Air whisked into the batter beforehand
- c) Hydrogen given off by the reaction
- d) Carbon dioxide given off by the reaction
8.Solution P has a pH of 6 and solution Q has a pH of 8. Which statement is right?
- a) P has more hydrogen ions, and P is the acidic one
- b) They hold the same number of hydrogen ions
- c) Q has more hydrogen ions, and Q is the acidic one
- d) P has more hydrogen ions, and Q is the acidic one

Acids, bases and salts · Class 10 Science · www.arenapublications.com/learn

Class 10 Science · 3 of 12

Metals, non-metals and the reactivity series

Rank metals by the activity series, work out the ion a metal or non-metal forms from its electron shells, and say how each band of the series is won from its ore and kept from corroding.

1.Match each description to the term the chapter gives it.
- A mineral rich enough to extract the metal from at a profit
- The soil and sand that come up with the ore
- Heating a sulphide ore strongly in plenty of air
- Heating a carbonate ore strongly in limited air
- The insoluble leavings that settle under the anode
- Ore
- Roasting
- Gangue
- Anode mud
- Calcination
2.Sort each metal by how the chapter says it is won from the earth.
Groups: Found in the native state · Reduction using carbon · Electrolysis of the molten compound
- Sodium
- Gold
- Iron
- Aluminium
- Zinc
- Silver
3.Calcium dropped into water starts to float after a few seconds. Why?
- a) It melts and spreads out into a thin film
- b) Calcium is less dense than water to begin with
- c) The water heats up and pushes it upwards
- d) Bubbles of hydrogen stick to its surface
4.Sodium is stored in a jar of kerosene oil rather than on a shelf. Why?
- a) Kerosene makes it easier to cut
- b) It loses its shine and stops conducting
- c) It reacts with oxygen so vigorously that it would catch fire in the open
- d) It dissolves in the damp air of a laboratory
5.A cell for refining copper is drawn below, with the two plates hanging in the solution and the battery marked. Tap the plate the pure copper builds up on.
Write the number of the part.
6.Galvanised iron sheets are coated with a thin layer of which metal?
- a) Aluminium
- b) Zinc
- c) Tin
- d) Chromium
7.Iron oxide is lit with aluminium powder and iron runs out molten. What is this reaction used for?
- a) Galvanising sheets of steel
- b) Turning a sulphide ore into an oxide
- c) Refining copper
- d) Joining railway tracks and cracked machine parts
8.Which pair of statements about ionic compounds matches what the chapter reports?
- a) They melt at high temperatures and dissolve in water rather than in kerosene
- b) They melt at low temperatures and dissolve in water rather than in kerosene
- c) They melt at high temperatures and dissolve in kerosene rather than in water
- d) They melt at low temperatures and dissolve in kerosene rather than in water

Metals, non-metals and the reactivity series · Class 10 Science · www.arenapublications.com/learn

Class 10 Science · 4 of 12

Carbon and its compounds

Explain why carbon shares electrons rather than trading them, tell a saturated compound from an unsaturated one, work along a homologous series, and name what soap does to oily dirt.

1.An unsaturated hydrocarbon is warmed with hydrogen over a palladium catalyst. What comes out?
- a) A saturated hydrocarbon
- b) A carboxylic acid
- c) An ester
- d) A haloalkane
2.Vegetable oil is hydrogenated with a nickel catalyst. What does the nickel do?
- a) It removes the double bonds by dissolving them
- b) It is used up as one of the reactants
- c) It joins the oil molecule in place of a hydrogen
- d) It makes the reaction go without being changed itself
3.Put the saturated chains in order of how many carbon atoms they hold, fewest first, beginning with "Methane".
- Butane
- Methane
- Pentane
- Propane
- Hexane
- Ethane
4.Why does carbon share electrons instead of gaining or losing four of them?
- a) Carbon atoms are too large to hold a charge
- b) Carbon has no electrons in its outermost shell to give away
- c) Six protons could neither hold ten electrons nor be stripped of four without great cost
- d) Carbon already has a full outermost shell
5.Why do detergents go on working in hard water where soap does not?
- a) They soften the water before they clean
- b) They dissolve the calcium and magnesium salts completely
- c) Their charged ends do not form insoluble precipitates with calcium and magnesium ions
- d) They are made without a hydrocarbon chain
6.Ethanoic acid is warmed with ethanol and a little concentrated sulphuric acid, and the mixture ends up smelling sweet. What is the sweet-smelling product called? Answer with one word.
7.Sort each compound by whether it carries a double or triple bond between carbon atoms.
Groups: Saturated · Unsaturated
- Propene
- Ethene
- Methane
- Ethyne
- Cyclohexane
- Ethane
8.Methane and chlorine are left together in sunlight, and one hydrogen of the methane is replaced by a chlorine atom. What kind of reaction is this?
- a) An oxidation reaction
- b) An addition reaction
- c) An esterification reaction
- d) A substitution reaction

Carbon and its compounds · Class 10 Science · www.arenapublications.com/learn

Class 10 Science · 5 of 12

Life processes

Trace food through the human gut and blood round the double circulation, say where each digestive juice acts, and explain how a plant moves water up and sugar down.

1.Sort each of these by where along the gut it does its work.
Groups: Mouth · Stomach · Small intestine
- Trypsin
- Pepsin
- Hydrochloric acid
- Lipase
- Salivary amylase
- Bile juice
2.A fish opens and closes its mouth far more often in a minute than you breathe. Why?
- a) There is much less oxygen dissolved in water than there is in air
- b) A fish needs more oxygen than a human being does
- c) Water is heavier than air and moves more slowly
- d) A fish has smaller lungs than a human being
3.Blood goes round and round, so pick a place to begin: starting from "The right atrium", put the stages of one full circuit in order.
- The left ventricle
- The right ventricle
- The right atrium
- The rest of the body
- The left atrium
- The lungs
4.Which pair of statements matches the two conducting tissues of a plant?
- a) Xylem carries water and sugar; phloem carries minerals
- b) Xylem carries sugar down; phloem carries water up
- c) Xylem carries water and minerals up; phloem carries the products of photosynthesis both ways
- d) Both carry water, xylem by day and phloem by night
5.Fat arrives in the small intestine as large globules. What does bile do about it?
- a) It absorbs the fat into the blood
- b) It breaks the globules into smaller ones so enzymes can reach more of the fat
- c) It stops the fat from reaching the pancreas
- d) It digests the fat completely into fatty acids and glycerol
6.Put the parts of the alimentary canal in the order food passes through them, starting with "Mouth".
- Oesophagus
- Large intestine
- Mouth
- Stomach
- Small intestine
- Anus
7.Match each stage in the break-down of glucose to what it produces.
- The first step, taken in the cytoplasm
- Fermentation in yeast
- Break-down of pyruvate in the mitochondria
- A muscle cell short of oxygen
- Ethanol and carbon dioxide
- Carbon dioxide and water
- Pyruvate
- Lactic acid
8.Why does a herbivore have a longer small intestine than a carnivore of the same size?
- a) A longer intestine absorbs more water
- b) Herbivores eat less often
- c) Plants contain more protein than meat does
- d) Cellulose from grass takes longer to digest than meat does

Life processes · Class 10 Science · www.arenapublications.com/learn

Class 10 Science · 6 of 12

Control and coordination

Follow an impulse along a neuron and round a reflex arc, name what each region of the brain looks after, and tell a plant's tropic growth from an animal's hormone response.

1.Why is iodised salt worth using?
- a) Iodine is the hormone that regulates blood sugar
- b) The pituitary needs iodine to make growth hormone
- c) Iodine replaces the salt lost in sweat
- d) The thyroid gland needs iodine to make thyroxin
2.Adrenaline is released when an animal is frightened. Which set of changes follows?
- a) The heart slows, blood goes to the digestive system, and breathing quietens
- b) The heart beats faster, blood is diverted to the skeletal muscles, and breathing quickens
- c) The heart beats faster and blood is diverted to the skin and gut
- d) Breathing quickens and the skeletal muscles are cut off from blood
3.How does the movement of a touch-me-not leaf differ from a shoot bending towards light?
- a) The leaf moves by growing on one side, and the shoot by losing water
- b) The leaf moves because it has muscle tissue and the shoot does not
- c) The leaf moves by cells gaining or losing water, with no growth involved
- d) Both are growth movements, but the leaf's is faster
4.Match each plant hormone to what it does.
- Auxin
- Gibberellin
- Cytokinin
- Abscisic acid
- Makes cells grow longer at the shoot tip
- Promotes cell division
- Inhibits growth
- Helps the stem grow
5.Match each hormone to the gland that makes it.
- Growth hormone
- Thyroxin
- Insulin
- Adrenaline
- Oestrogen
- Testosterone
- Ovaries
- Thyroid gland
- Pituitary gland
- Pancreas
- Adrenal gland
- Testes
6.A shoot bends towards a window. Where has the auxin gone, and what has it done?
- a) To the lit side, where it has made the cells grow longer
- b) To the root, where it has made the root bend too
- c) To the shady side, where it has stopped the cells growing
- d) To the shady side, where it has made the cells grow longer
7.One neuron is drawn below. Tap the part along which the electrical impulse travels away from the cell body.
Write the number of the part.
8.Why is a reflex arc worth having, when the brain could give the same instruction?
- a) The spinal cord is closer to the brain than the hand is
- b) Reflex arcs use less energy than thinking does
- c) The brain cannot reach the muscles of the hand
- d) Thinking takes long enough that the damage would be done

Control and coordination · Class 10 Science · www.arenapublications.com/learn

Class 10 Science · 7 of 12

How organisms reproduce

Tell the asexual modes apart by the organism that uses each, follow pollen from stigma to seed and an egg from ovary to implantation, and say why variation is worth the cost of two parents.

1.Match each part to the job it does.
- The testes
- The vas deferens
- The ovaries
- The oviduct
- The placenta
- Carries the sperms from the testes
- Carries the egg towards the uterus
- Make the sperms
- Passes glucose and oxygen from the mother to the embryo
- Make the eggs
2.A population of bacteria lives in temperate water, and the water warms. Most die; a few carrying a heat-resistant variation live and multiply. What does this show?
- a) Variation protects each individual from any change
- b) Warm water causes bacteria to develop resistance
- c) Asexual reproduction produces identical offspring
- d) Variation gives a species a chance of surviving a change in its niche
3.Put the stages of fertilisation in a flowering plant in order, starting with "Pollen lands on a suitable stigma".
- The male germ-cell fuses with the egg cell in the ovule
- The ovule takes a tough coat and becomes a seed
- The ovary ripens into a fruit
- Pollen lands on a suitable stigma
- The zygote divides again and again to form an embryo
- A tube grows out of the pollen grain and travels down the style
4.Put these stages in order, starting with "One of the ovaries releases an egg".
- One of the ovaries releases an egg
- The zygote divides into a ball of cells
- A sperm meets the egg in the oviduct
- The embryo is implanted in the lining of the uterus
- The egg travels along the oviduct
5.What does the placenta's structure — villi on the embryo's side, blood spaces on the mother's — give the embryo?
- a) A barrier that keeps the mother's blood entirely separate
- b) A store of food the embryo draws on directly
- c) A muscular wall that pushes nutrients through
- d) A large surface for glucose and oxygen to pass across, and for wastes to pass back
6.Which of these is a viral infection that can be passed on during the sexual act, according to the chapter?
- a) HIV-AIDS
- b) Goitre
- c) Syphilis
- d) Gonorrhoea
7.Why do the testes lie in the scrotum, outside the abdominal cavity?
- a) There is no room for them inside the abdomen
- b) It keeps them away from the urinary bladder
- c) It shortens the path the sperms have to travel
- d) Sperm formation needs a temperature lower than the rest of the body's
8.Banana, orange, rose and jasmine are raised by vegetative propagation. What makes it the method of choice for them?
- a) Their seeds produce plants that flower too early
- b) They have lost the capacity to produce seeds
- c) Their flowers cannot be pollinated by insects
- d) Their seeds take too long to germinate

How organisms reproduce · Class 10 Science · www.arenapublications.com/learn

Class 10 Science · 8 of 12

Heredity

Work out the ratios of a Mendelian cross, tell a dominant trait from a recessive one, and explain how chromosomes let two traits be inherited independently and how they settle a child's sex.

1.How does a gene end up controlling how tall a plant grows?
- a) It stretches the cells of the stem directly
- b) It decides how much water the roots take up
- c) It sets how efficient an enzyme is, which sets how much growth hormone is made
- d) It counts the number of cells the stem may have
2.What was new about Mendel's way of working, compared with others who had bred peas before him?
- a) He kept count of the individuals showing each trait in each generation
- b) He was the first to cross two different pea plants
- c) He was the first to grow peas in a monastery garden
- d) He used a microscope to look at the germ-cells
3.In some reptiles, what decides whether the animals developing in the eggs will be male or female?
- a) The size of the egg
- b) The sex chromosomes inherited from the father
- c) The order in which the eggs were laid
- d) The temperature at which the fertilised eggs are kept
4.Four second-generation pea plants are drawn to scale below. Tap the one that must have inherited two copies of the recessive factor.
Write the number of the part.
5.Sort each of Mendel's pea traits as the chapter classifies it.
Groups: Dominant · Recessive
- Tall plants
- Short plants
- Wrinkled seeds
- Round seeds
6.Mendel counted 315 round yellow, 108 round green, 101 wrinkled yellow and 32 wrinkled green seeds. Which proportion is that closest to?
- a) 9 : 3 : 3 : 1
- b) 3 : 1 : 1 : 1
- c) 9 : 6 : 1
- d) 1 : 1 : 1 : 1
7.Put the stages of Mendel's one-character experiment in order, starting with "Cross a tall pea plant with a short one".
- Cross a tall pea plant with a short one
- One quarter of the second generation comes out short
- Let those first-generation plants self-pollinate
- The whole of the first generation comes out tall
8.The short plants reappear in the second generation, after a first generation that was tall throughout. What does that show?
- a) The short trait was created afresh in the second generation
- b) Both traits were inherited by the first generation, with one of them expressed
- c) Self-pollination changed the tall factor into a short one
- d) The first generation was not really tall

Heredity · Class 10 Science · www.arenapublications.com/learn

Class 10 Science · 9 of 12

Reflection and refraction of light

Apply the New Cartesian Sign Convention to the mirror and lens formulae, work out magnification and the power of a lens, and read a refractive index for what it says about the speed of light.

1.Under the New Cartesian Sign Convention, why does the object distance come out negative?
- a) The object is below the principal axis
- b) Object distances are measured from the centre of curvature
- c) The object is placed to the left of the mirror, and distances to the left of the pole count negative
- d) The object is closer to the mirror than the image is
2.For a concave mirror, match each position of the object to where the image forms.
- Object at infinity
- Object beyond C
- Object at C
- Object between C and F
- Image beyond C
- Image at the focus F
- Image at C
- Image between F and C
3.For that same lens the image distance is v = +30 and the object distance is u = -15. Magnification for a lens is m = v/u. What is m? Answer with a number, sign included.
4.A lens has a focal length of 0.5 metres. Power is the reciprocal of the focal length in metres. What is its power, in dioptres? Answer with a number.
5.The refractive index of water is 1.33. What does that number say?
- a) Water is 1.33 times as dense as air
- b) A ray bends through 1.33 degrees on entering water
- c) Light travels 1.33 times as fast in water as it does in air
- d) Light travels 1.33 times as fast in air as it does in water
6.Sort each arrangement by the kind of image it gives.
Groups: Real and inverted · Virtual and erect
- Object between the pole and the focus of a concave mirror
- Object beyond the centre of curvature of a concave mirror
- Object between the centre of curvature and the focus of a concave mirror
- Object at the centre of curvature of a concave mirror
- Object anywhere in front of a convex mirror
7.An optician puts two lenses in contact in a testing frame, one of power +2.0 D and one of +0.25 D. What is the power of the combination?
- a) +2.0 D
- b) +2.25 D
- c) +0.5 D
- d) +1.125 D
8.An object sits at u = -15 in front of a convex lens whose focal length is f = +10. Use 1/v = 1/f + 1/u to find the image distance v. Answer with a number, sign included.

Reflection and refraction of light · Class 10 Science · www.arenapublications.com/learn

Class 10 Science · 10 of 12

The human eye and the colourful world

Name the parts of the eye and what each does, tell myopia from hypermetropia and pick the lens that corrects each, and explain dispersion, twinkling and the blue of the sky by refraction and scattering.

1.Sort each description by the defect of vision it belongs to.
Groups: Myopia · Hypermetropia
- The image of a distant object forms in front of the retina
- Cannot see nearby objects distinctly
- The far point is nearer than infinity
- Light from a close object is focussed behind the retina
- The near point is farther away than it should be
- Cannot see distant objects distinctly
2.White light passing through a prism comes out as a band of seven colours. What is this splitting called? Answer with one word.
3.Newton passed his spectrum through a second identical prism placed upside down, and got white light out again. What did that show him?
- a) The second prism destroyed the colours
- b) A prism can bend light but not split it
- c) Sunlight is made up of the seven colours the first prism separated
- d) The first prism had added colours to the light
4.Which colour bends the most as it passes through a prism, and which the least?
- a) Violet the most, red the least
- b) Green the most, violet the least
- c) Red the most, violet the least
- d) They bend equally, and separate by speed
5.Someone needs both distant and near vision corrected and is given bi-focal lenses. What is in the upper portion?
- a) A concave lens, for distant vision
- b) A convex lens, for near vision
- c) A convex lens, for distant vision
- d) A concave lens, for near vision
6.Why does the sky look dark to a passenger flying very high up?
- a) The Sun is closer and outshines the sky
- b) There is too little scattering at that height
- c) The window glass absorbs the blue light
- d) The air is colder and refracts less
7.You look up from a book to the far end of the street. What have the ciliary muscles just done?
- a) Relaxed, letting the lens thin out so its focal length increases
- b) Contracted, letting the lens thin out so its focal length increases
- c) Relaxed, making the lens thicker so its focal length decreases
- d) Contracted, making the lens thicker so its focal length decreases
8.Why are danger signal lights red?
- a) Red is scattered most, so it spreads out further
- b) Red is the colour the eye is most sensitive to at night
- c) Red is scattered least by fog or smoke, so it carries its colour a long way
- d) Red light travels faster through fog

The human eye and the colourful world · Class 10 Science · www.arenapublications.com/learn

Class 10 Science · 11 of 12

Electricity

Use Ohm's law and the series and parallel rules to find a resistance or a current, work out electric power and energy, and say why a heater's element is an alloy and a fuse is a weak link.

1.Sort each material by what the chapter says it is used for.
Groups: Filaments of electric bulbs · Electrical transmission lines · Heating devices such as an electric iron
- Tungsten
- Aluminium
- Copper
- An alloy such as constantan
2.Which statement is Ohm's law as the chapter states it?
- a) The potential difference across a metallic wire is proportional to its length
- b) The resistance of a metallic wire is proportional to the current through it
- c) The potential difference across a metallic wire is proportional to the current through it, at constant temperature
- d) The current through a metallic wire is proportional to its resistance
3.Sort each statement by the kind of circuit it describes.
Groups: Series · Parallel
- The currents through the branches add up to the total current
- The current is the same through each resistor
- When one component fails, nothing in the circuit works
- Each gadget can draw the current it needs
- The potential difference is the same across each resistor
- The potential differences across the resistors add up to the supply voltage
4.A 6 Ω resistor and a 3 Ω resistor are joined in parallel. What is the equivalent resistance, in ohms? Answer with a number.
5.Match each electrical quantity to its SI unit.
- Electric current
- Potential difference
- Resistance
- Electric power
- Electrical energy sold commercially
- Kilowatt hour
- Watt
- Ohm
- Volt
- Ampere
6.A lamp of resistance 100 Ω is connected across a 220 V supply. What current does it draw, in amperes? Answer with a number.
7.A potential difference of 6 V across a resistor drives a current of 0.5 A through it. What is its resistance, in ohms? Answer with a number.
8.A wire is replaced by another of the same material and thickness but twice the length. What happens to its resistance?
- a) It stays the same
- b) It falls to a quarter
- c) It doubles
- d) It halves

Electricity · Class 10 Science · www.arenapublications.com/learn

Class 10 Science · 12 of 12

Magnetic effects of electric current

Read a field-line diagram for direction and strength, pick the right-hand thumb rule or Fleming's left-hand rule for the job, and explain what the earth wire and the fuse are doing in a house circuit.

1.A house has two separate circuits, one rated 15 A and one rated 5 A. Which appliances go on which?
- a) Lighting on both, with the 15 A circuit kept in reserve
- b) Everything on the 15 A circuit, with the 5 A one kept spare
- c) Geysers and air coolers on the 15 A circuit; bulbs and fans on the 5 A one
- d) Bulbs and fans on the 15 A circuit; geysers and air coolers on the 5 A one
2.Why is the metallic body of a refrigerator connected to the earth wire?
- a) It gives leaking current a low-resistance path, so the body stays at the earth's potential
- b) It joins the body to the neutral wire
- c) It raises the potential of the body above the earth's
- d) It stops the refrigerator from drawing too much current
3.Match each wire of the domestic supply to the colour of its insulation.
- The live wire
- The neutral wire
- The earth wire
- Black
- Red
- Green
4.A single circular turn of wire makes a field of a certain strength at the centre of the loop. A coil of 12 such turns carries the same current. How many times that strength is the field at the centre now? Answer with a number.
5.What do the parallel straight field lines inside a current-carrying solenoid tell you?
- a) The solenoid has no poles
- b) There is no field inside the solenoid
- c) The field inside is stronger at the ends than in the middle
- d) The field is the same at points inside it — it is uniform
6.Field lines round a bar magnet are drawn below. Tap the part of the picture where the field is strongest.
Write the number of the part.
7.In Fleming's left-hand rule, what does the first finger point along?
- a) The magnetic field
- b) The motion of the electrons
- c) The force on the conductor
- d) The current
8.Why can two magnetic field lines not cross?
- a) A compass at the crossing would have to point two ways at once
- b) The lines are drawn too thick to overlap
- c) The two fields would cancel out at the crossing
- d) Field lines are closed curves, and closed curves cannot meet

Magnetic effects of electric current · Class 10 Science · www.arenapublications.com/learn

Answer keys — Class 10 Science

In the same order as the worksheets.