Q: Question 1(ii)The kinetic energy of a given body depends on the:positioncentre of gravity of bodymomentumdisplacement

momentumReason — As kinetic energy = 12\dfrac{1}{2}21 mv 2If we multiply and divide by m then we get, (mv)22m\dfrac{\text{(mv)}^2}{2\text{m}}2m(mv)2As mv = momentum (p), sokinetic energy = p22m\dfrac{\text{p}^2}{2\text{m}}2mp2Therefore, kinetic energy of a given body depends on the momentum.

Question 1

Question 1(ii)The kinetic energy of a given body depends on the:positioncentre of gravity of bodymomentumdisplacement

Accepted Answer

momentumReason — As kinetic energy = 12\dfrac{1}{2}21​ mv 2If we multiply and divide by m then we get, (mv)22m\dfrac{	ext{(mv)}^2}{2	ext{m}}2m(mv)2​As mv = momentum (p), sokinetic energy = p22m\dfrac{	ext{p}^2}{2	ext{m}}2mp2​Therefore, kinetic energy of a given body depends on the momentum.

Question 2

Question 1(iii)For burning of coal in a thermoelectric station, the energy conversion taking place is:chemical to heat to mechanicalchemical to heat to mechanical to electricalchemical to heat to lightheat to chemical to mechanical

Accepted Answer

chemical to heat to mechanical to electrical.Reason — A thermal power station is a type of power station in which heat energy is converted to electrical energy.Here, the chemical energy of coal is changed into heat energy, which is transferred to steam. Then the heat energy of steam changes into mechanical energy of turbine that is further changed into electrical energy.

Question 3

Question 1(xiv)When a ray of light enters from a denser medium to a rarer medium then:the light ray bends towards the normalthe speed of light increasesthe angle of incidence is greater than the angle of refractionits wavelength decreases.

Accepted Answer

the speed of light increasesReason — The speed of light increases when it enters from a denser medium to a rarer medium. Lower density of the rarer medium causes less interaction between photons and particles. This reduces the scattering and results in a higher speed.

Question 4

Question 2(iii)A lever is shown below.(a) Identify the type of lever.(b) Calculate its mechanical advantage.

Accepted Answer

(a) It is a class III lever.(b) Mechanical advantage = effort armload arm\dfrac{\text{effort arm}}{\text{load arm}}load armeffort arm​ = 0.10.1+0.4\dfrac{0.1}{0.1 + 0.4}0.1+0.40.1​=0.10.5=15=0.2= \dfrac{0.1}{0.5} \[1em] = \dfrac{1}{5} \[1em] = 0.2=0.50.1​=51​=0.2

Question 5

Question 2(iv)Two bodies A and B have same kinetic energies. Compare their velocities if mass of A is four times the mass of B.

Accepted Answer

Considering Body A:Let mass of body A = ma = 4mLet kinetic energy of body A = KLet velocity of body A = VaConsidering Body B:Mass of body B = mb = m [∵ mass of A is four times the mass of B]Kinetic energy of body B = K [∵ A and B have same kinetic energies]Let velocity of body B = VbGiven, A and B have same kinetic energies,∴ 12\dfrac{\text{1}}{\text{2}}21​ 4mVa2 = 12\dfrac{\text{1}}{\text{2}}21​mVb24mVa2 = mVb2Va2Vb2=14⇒VaVb=14⇒VaVb=12\dfrac{\text{V}_a^2}{\text{V}_b^2} = \dfrac{\text{1}}{\text{4}} \[1em] \Rightarrow \dfrac{\text{V}_a}{\text{V}_b} = \sqrt{\dfrac{\text{1}}{\text{4}}} \[1em] \Rightarrow \dfrac{\text{V}_a}{\text{V}_b} = \dfrac{1}{2}Vb2​Va2​​=41​⇒Vb​Va​​=41​​⇒Vb​Va​​=21​Hence, Va : Vb = 1 : 2 or velocity of body B is two times the velocity of body A.

Question 6

Question 2(v)Draw a graph of potential energy vs height from the ground for a body thrown vertically upwards.

Accepted Answer

Graph of potential energy vs height from the ground for a body thrown vertically upwards is shown below:

Question 7

Question 2(vi)Two copper wires A and B are of the same thickness and are at the room temperature. If the length of A is twice the length of B then :(a) Compare their resistances(b) Compare their resistivity

Accepted Answer

(a) Let the length of wire B be L and that of A be 2LR= ρlengtharea\dfrac{	ext{length}}{	ext{area}}arealength​As area and specific resistance (ρ) are same for both wires A and B,Hence,RaRb\dfrac{	ext{R}_a}{	ext{R}_b}Rb​Ra​​ = lalb\dfrac{	ext{l}_a}{	ext{l}_b}lb​la​​ = 2LL\dfrac{	ext{2L}}{	ext{L}}L2L​ = 21\dfrac{	ext{2}}{	ext{1}}12​Hence, the ratio between resistances A and B is 2 : 1(b) Both the wires will have the same specific resistance because the specific resistance is a characteristic property of the material and as both the wires are of copper hence both will have same specific resistance.

Question 8

Question 2(vii)(a) Name the waves used for echo depth sounding.(b) Give one reason for their use in the above application

Accepted Answer

(a) The waves used for echo depth sounding are ultrasonic waves.(b) Ultrasonic waves can travel undeviated through a long distance and so they are used for echo depth sounding.

Question 9

Question 3(i)(a) Refer to the diagram given below. A lens with two different refractive indices is shown. If the rays are coming from a distant object, then how many images will be seen?(b) A glass lens always forms a virtual, erect and diminished image of an object kept in front of it. Identify the lens.

Accepted Answer

(a) Two images will be seen.Reason — According to the lens maker formula :1f\dfrac{1}{	ext{f}}f1​ = (μ - 1)(1R1\dfrac{1}{	ext{R}_1}R1​1​ - 1R2\dfrac{1}{	ext{R}_2}R2​1​)Focal length is a function of refractive index, hence for two different refractive index there will be two different focal lengths.Two different focal length implies two different images for same object. Hence 2 images will be formed.(b) Concave lens

Question 10

Question 3(ii)It is observed that the house circuits are arranged in a parallel combination. Give two advantages of this arrangement.

Accepted Answer

(a) Two advantages of this arrangement are :Each appliance operates independently without being affected by the presence or working of the other appliances.Each appliance gets connected to 220 V supply (= its voltage rating) for its normal working.

Question 11

Question 3(iii)A transformer is used to change a high alternating e.m.f. to a low alternating e.m.f. of the same frequency.(a) Identify the type of transformer used for the above purpose.(b) State whether the turns ratio of the above transformer is = 1 or >1 or <1.

Accepted Answer

(a) Step down transformer(b) turns ratio is n < 1, i.e., number of turns in the secondary are less than the number of turns in the primary.

Question 12

Question 3(iv)A solid of mass 60 g at 100°C is placed in 150 g of water at 20°C. The final steady temperature is 25°C. Calculate the heat capacity of solid?[sp. heat capacity of water = 4.2 J g-1 K-1 ]

Accepted Answer

Given,Mass of solid (m) = 60 gFall in temperature of solid = (100 - 25) = 75°CRise in temperature of water = (25 - 20) = 5°CLet specific heat capacity of solid be c.Heat energy given by solid = mc△t= 60 x c x 75 = 4500 x c .....(1)Heat energy taken by water = 150 × 4.2 × 5 = 3150 .....(2)Assuming that there is no loss of heat energy,Heat energy given by solid = Heat energy taken by water.Equating equations 1 & 2, we get,4500×c=3150c=31504500c=0.7 J g−1K−14500 \times c = 3150 \[0.5em] c = \dfrac{3150}{4500} \[0.5em] c = 0.7 \text{ J g}^{-1} \text{K}^{-1} \[0.5em]4500×c=3150c=45003150​c=0.7 J g−1K−1specific heat capacity of the solid = 0.7 J g-1 K-1Heat capacity of solid = mass (m) x specific heat capacity = 60 x 0.7 = 42 J K-1Hence, Heat capacity of solid = 42 J K-1

Question 13

Question 3(v)What is a nuclear waste? State one method to dispose it safely.

Accepted Answer

The radioactive material after its use such as nuclear power generation, nuclear weapons production, and nuclear medicine is known as nuclear waste.The nuclear waste obtained from laboratories, hospitals, scientific establishments or power plants must be first kept in thick casks and then they must be buried in the specially constructed deep underground stores. These underground stores must be far away from the populated areas.

Question 14

Question 4(i)The diagram below shows a fish in the tank and its image seen in the surface of water.(a) Name the phenomenon responsible for the formation of this image.(b) Complete the path of the ray through the glass prism of critical angle 42° till it emerges out of the prism.

Accepted Answer

(a) Total Internal ReflectionReason — The image of the fish seen at the surface of water is due to total internal reflection as shown in the ray diagram below:(b) Below diagram shows the completed path of the ray till it emerges out of the prism:

Question 15

Question 5(i)An object is placed at a distance 24 cm in front of a convex lens of focal length 8 cm.(a) What is the nature of the image so formed?(b) Calculate the distance of the image from the lens.

Accepted Answer

(a) Real and inverted image is formed.(b) Given, focal length = 8 cmObject distance (u) = -24 cmImage distance (v) = ?From lens formula —1v−1u=1f\dfrac{1}{v} - \dfrac{1}{u} = \dfrac{1}{f} \[1em]v1​−u1​=f1​Substituting the values in the formula we get,1v−1−24=181v+124=181v=18−124⇒1v=3−124⇒1v=224⇒1v=112⇒v=12\dfrac{1}{\text{v}} - \dfrac{1}{-24} = \dfrac{1}{8} \[1em] \dfrac{1}{\text{v}} + \dfrac{1}{24} = \dfrac{1}{8} \[1em] \dfrac{1}{\text{v}} = \dfrac{1}{8} - \dfrac{1}{24}\[1em] \Rightarrow \dfrac{1}{\text{v}} = \dfrac{3 - 1}{24} \[1em] \Rightarrow \dfrac{1}{\text{v}} = \dfrac{2}{24} \[1em] \Rightarrow \dfrac{1}{\text{v}} = \dfrac{1}{12} \[1em] \Rightarrow v = 12v1​−−241​=81​v1​+241​=81​v1​=81​−241​⇒v1​=243−1​⇒v1​=242​⇒v1​=121​⇒v=12∴ The image is formed at a distance of 12 cm behind the lens.

Question 16

Question 5(ii)When sunlight passes through water droplets in the atmosphere it gets dispersed into its constituent colours forming a rainbow. A similar phenomenon is observed when white light passes through a prism.(a) Which colour will show the maximum angle of deviation and which colour will show the minimum angle of deviation?(b) If instead of sunlight, a green-coloured ray is passed through a glass prism. What will be the colour of the emergent ray?

Accepted Answer

(a) When sunlight passes through water droplets in the atmosphere or through a prism, violet light shows the maximum angle of deviation, while red light shows the minimum angle of deviation.(b) The colour of emergent ray will be green. A prism does not change the colour of light. It just disperses white light into its constituent colours.

Question 17

Question 5(iii)(a) Mixture of red + blue + green is passed through a convex lens as shown in the diagram below. State whether the ray passes through a single point or through different points on principle axis after refraction.(b) Name the invisible radiations which can be obtained using quartz prism? State one use of these radiations.(c) Name one radiations having wavelength longer than the wavelength of these radiations.

Accepted Answer

(a) The ray will pass through different points on principle axis after refraction through the convex lens. Red colour will deviate the least, followed by green and then blue will deviate the most.(b) Ultraviolet radiations. Ultraviolet radiations are used for sterilising air, surgical equipment, etc.(c) Infrared radiation.

Question 18

Question 6(i)Sumit and Sachin went for a trek and during the journey they visited a cottage. They suspended their bags to the two ropes hanging from P and Q on a wheel capable of rotating around O. Sumit suspended his bag to the rope Q and Sachin suspended his bag from the rope P. The wheel remained in equilibrium.(a) State with a reason who is carrying a heavier bag.(b) Based on the principle of moments, write a mathematical relation that can be used to determine the weight (W) of Sachin's bag, given that the weight of Sumit's bag is 18 kgf.

Accepted Answer

(a) At equilibrium clockwise moment = anticlockwise momentMoment = force x perpendicular distanceWt. of Sachin's bag x OP = Wt. of Sumit's bag x ORAs OR < OP. Hence, Wt. of Sumit's bag > Wt. of Sachin's bag.Hence, Sumit's bag is heavier than Sachin's bag(b) Given,Wt. of Sumit's bag = 18 kgfLet wt. of Sumit's bag be WAt equilibrium,Clockwise moment = Anticlockwise momentW x OP = 18 x ORW = 18×OROP\dfrac{18 	imes 	ext{OR}}{	ext{OP}}OP18×OR​

Question 19

Question 6(ii)The diagram below shows a block and tackle system.(a) Copy and complete the labelled diagram showing the correct connection of the tackle, the direction of the forces involved to obtain maximum V.R. with the convenient direction.(b) Calculate the M.A. of this pulley system if its efficiency is 80%.

Accepted Answer

(a) The completed diagram is given below:(b) η = 80% givenV.R. = n = 3,M.A. =?η = M.A.V.R.\dfrac{	ext{M.A.}}{	ext{V.R.}}V.R.M.A.​80100\dfrac{	ext{80}}{	ext{100}}10080​ = M.A.3\dfrac{	ext{M.A.}}{	ext{3}}3M.A.​M.A. = 80100\dfrac{	ext{80}}{	ext{100}}10080​ x 3= 240100\dfrac{	ext{240}}{	ext{100}}100240​ = 2.4

Question 20

Question 6(iii)The figure below shows a simple pendulum of mass 200 g. It is displaced from the mean position A to the extreme position B. The potential energy at the position A is zero. At the position B the pendulum bob is raised by 5 m.(a) What is the potential energy of the pendulum at the position B?(b) What is the total mechanical energy at point C?(c) What is the speed of the bob at the position A when released from B?(Take g = 10 ms-2 and given that there is no loss of energy.)

Accepted Answer

Given,h = 5 mm = 200 g = 0.2 kgg = 10 ms-2(i) Potential energy UB at B is given byUB = m x g x hSubstituting the values we get,UB = 0.2 x 10 x 5 = 10 JHence, the potential energy of the pendulum at the position B = 10 J(ii) Total mechanical energy at point C = 10 JThe total mechanical energy is same at all points of the path due to conservation of mechanical energy.(iii) At A, bob has only kinetic energy which is equal to potential energy at B,Therefore,12×m×(vA)2=UB0.5×0.2×(vA)2=10(vA)2=100.1⇒vA=100⇒vA=10 m s−1\dfrac{1}{2} \times m \times (v_A)^{2} = U_B \[0.5em] 0.5 \times 0.2 \times (v_A)^{2} = 10 \[0.5em] (v_A)^{2} = \dfrac{10}{0.1} \[0.5em] \Rightarrow v_A = \sqrt{100} \[0.5em] \Rightarrow v_A = 10 \text{ m s}^{-1}21​×m×(vA​)2=UB​0.5×0.2×(vA​)2=10(vA​)2=0.110​⇒vA​=100​⇒vA​=10 m s−1

Solved 2024 Specimen Paper ICSE Class 10 Physics

Section A 40 Marks

Section B 40 Marks