Page 1 CBSE | Physics Sample Paper 4 Solution CBSE Board Class XI Physics Sample Paper-4 Solution 1. 4 2. Pressure or energy per unit volume 3. Greater torque will be applied if force arm is more as sin rF ?? ? . 4. Kinetic energy is always positive, potential energy can be negative. 5. Yes, it is not an intrinsic property of the spring. It not only depends on the material in the spring but also the length and shape of the spring. 6. The statement is false. This is because when steel and rubber of same length and cross- sectional area are subjected to same load, then the extension produced in steel is much less than that of rubber. So the ratio of stress to strain or Young’s modulus for steel is much greater than that of rubber. 7. rad/s. Page 2 CBSE | Physics Sample Paper 4 Solution CBSE Board Class XI Physics Sample Paper-4 Solution 1. 4 2. Pressure or energy per unit volume 3. Greater torque will be applied if force arm is more as sin rF ?? ? . 4. Kinetic energy is always positive, potential energy can be negative. 5. Yes, it is not an intrinsic property of the spring. It not only depends on the material in the spring but also the length and shape of the spring. 6. The statement is false. This is because when steel and rubber of same length and cross- sectional area are subjected to same load, then the extension produced in steel is much less than that of rubber. So the ratio of stress to strain or Young’s modulus for steel is much greater than that of rubber. 7. rad/s. CBSE | Physics Sample Paper 4 Solution 8. Impulse, 21 J F t P P ? ? ? ? For the same change in momentum if t ? is increased then F decreases. If the cricketer pulls back his hands, he increases t ? , and Force on his hand decreases and he does not hurt himself. 9. Horizontal Range = Maximum height 2 2 2 sin 2 ? s in ? 2 uu gg ? tan ? =4 -1 4 ? = t a n OR No. Even though the particle is moving with constant speed along the circle, it is accelerating as its velocity continuously changes. The acceleration vector is drawn towards the centre of the circle. So as the particle moves in uniform circular motion, the acceleration vector changes direction continuously and it is not a constant vector. 10. Particle velocity is the velocity of the particles of the medium. Wave velocity is the speed at which the wave disturbance travels through the medium. 11. Let 12 mm ? 12 PP ? 2 22 12 12 12 2 ; 22 ? ?? P KE m PP KE KE mm As 1 2 1 2 and P P m m ?? Therefore KE 2 will be greater than KE 1. Page 3 CBSE | Physics Sample Paper 4 Solution CBSE Board Class XI Physics Sample Paper-4 Solution 1. 4 2. Pressure or energy per unit volume 3. Greater torque will be applied if force arm is more as sin rF ?? ? . 4. Kinetic energy is always positive, potential energy can be negative. 5. Yes, it is not an intrinsic property of the spring. It not only depends on the material in the spring but also the length and shape of the spring. 6. The statement is false. This is because when steel and rubber of same length and cross- sectional area are subjected to same load, then the extension produced in steel is much less than that of rubber. So the ratio of stress to strain or Young’s modulus for steel is much greater than that of rubber. 7. rad/s. CBSE | Physics Sample Paper 4 Solution 8. Impulse, 21 J F t P P ? ? ? ? For the same change in momentum if t ? is increased then F decreases. If the cricketer pulls back his hands, he increases t ? , and Force on his hand decreases and he does not hurt himself. 9. Horizontal Range = Maximum height 2 2 2 sin 2 ? s in ? 2 uu gg ? tan ? =4 -1 4 ? = t a n OR No. Even though the particle is moving with constant speed along the circle, it is accelerating as its velocity continuously changes. The acceleration vector is drawn towards the centre of the circle. So as the particle moves in uniform circular motion, the acceleration vector changes direction continuously and it is not a constant vector. 10. Particle velocity is the velocity of the particles of the medium. Wave velocity is the speed at which the wave disturbance travels through the medium. 11. Let 12 mm ? 12 PP ? 2 22 12 12 12 2 ; 22 ? ?? P KE m PP KE KE mm As 1 2 1 2 and P P m m ?? Therefore KE 2 will be greater than KE 1. CBSE | Physics Sample Paper 4 Solution 12. The law of equipartition of energy states that if a system is in equilibrium at absolute temperature T, the total energy is distributed equally in different energy modes of absorption, the energy in each mode being equal to 1 . 2 B kT 13. An expansion or contraction in which no heat enters or leaves the system is called an adiabatic process. In this the temperature of the system can change. In an isothermal process, the gas expands or is compressed at constant temperature. To maintain constant temperature heat can be transferred into or out of the system. 14. Change in momentum 10 2 cos45 2 5 cos45 2 ? ? ? ? oo mv v 15. 2 1 2 mv mgh ? Dimensions of LHS are ? ? 2 1 2 2 M LT MLT ?? ? ? ? ? ? ? ? ? ? Dimension of RHS are ? ? ? ? 2 2 2 M LT L MLT ?? ? ? ? ? ? ? ? ? ? Since the dimensions of quantity on LHS is equal to the dimensions of quantity on RHS. Thus the given expression is correct. Page 4 CBSE | Physics Sample Paper 4 Solution CBSE Board Class XI Physics Sample Paper-4 Solution 1. 4 2. Pressure or energy per unit volume 3. Greater torque will be applied if force arm is more as sin rF ?? ? . 4. Kinetic energy is always positive, potential energy can be negative. 5. Yes, it is not an intrinsic property of the spring. It not only depends on the material in the spring but also the length and shape of the spring. 6. The statement is false. This is because when steel and rubber of same length and cross- sectional area are subjected to same load, then the extension produced in steel is much less than that of rubber. So the ratio of stress to strain or Young’s modulus for steel is much greater than that of rubber. 7. rad/s. CBSE | Physics Sample Paper 4 Solution 8. Impulse, 21 J F t P P ? ? ? ? For the same change in momentum if t ? is increased then F decreases. If the cricketer pulls back his hands, he increases t ? , and Force on his hand decreases and he does not hurt himself. 9. Horizontal Range = Maximum height 2 2 2 sin 2 ? s in ? 2 uu gg ? tan ? =4 -1 4 ? = t a n OR No. Even though the particle is moving with constant speed along the circle, it is accelerating as its velocity continuously changes. The acceleration vector is drawn towards the centre of the circle. So as the particle moves in uniform circular motion, the acceleration vector changes direction continuously and it is not a constant vector. 10. Particle velocity is the velocity of the particles of the medium. Wave velocity is the speed at which the wave disturbance travels through the medium. 11. Let 12 mm ? 12 PP ? 2 22 12 12 12 2 ; 22 ? ?? P KE m PP KE KE mm As 1 2 1 2 and P P m m ?? Therefore KE 2 will be greater than KE 1. CBSE | Physics Sample Paper 4 Solution 12. The law of equipartition of energy states that if a system is in equilibrium at absolute temperature T, the total energy is distributed equally in different energy modes of absorption, the energy in each mode being equal to 1 . 2 B kT 13. An expansion or contraction in which no heat enters or leaves the system is called an adiabatic process. In this the temperature of the system can change. In an isothermal process, the gas expands or is compressed at constant temperature. To maintain constant temperature heat can be transferred into or out of the system. 14. Change in momentum 10 2 cos45 2 5 cos45 2 ? ? ? ? oo mv v 15. 2 1 2 mv mgh ? Dimensions of LHS are ? ? 2 1 2 2 M LT MLT ?? ? ? ? ? ? ? ? ? ? Dimension of RHS are ? ? ? ? 2 2 2 M LT L MLT ?? ? ? ? ? ? ? ? ? ? Since the dimensions of quantity on LHS is equal to the dimensions of quantity on RHS. Thus the given expression is correct. CBSE | Physics Sample Paper 4 Solution 16. The position of a particle is given by ? ? 2 ˆ ˆˆ 5 6 10 S t ti t j k ? ? ? ? ? ? ? ? ? () ˆˆ 5 12 ˆ 12 ? ? ? ?? ds t v t i t j dt dv t a t j dt ? ? ? ? 22 2 ˆˆ 1 5 12 5 12 13 / 1 12 12 / ? ? ? ? ? ? ?? ? v t i j v m s a t j a m s 17. Kinetic energy of a satellite 2 GMm E r ?? Potential energy of a satellite 2 GMm E r ? ? ? ? Total energy KE PE ?? ? ? 2 E E E ? ? ? ? ? 18. (i) A body with large reflectivity is a poor absorber. Hence it is also a poor emitter. (ii) To convert water at 100 o c to steam at 100 o c the water needs to absorb the latent heat of vaporization. So it is more efficient to use steam rather than water because when steam at 100 o c is circulated it releases latent heat in addition to heat released due to change in temperature. Page 5 CBSE | Physics Sample Paper 4 Solution CBSE Board Class XI Physics Sample Paper-4 Solution 1. 4 2. Pressure or energy per unit volume 3. Greater torque will be applied if force arm is more as sin rF ?? ? . 4. Kinetic energy is always positive, potential energy can be negative. 5. Yes, it is not an intrinsic property of the spring. It not only depends on the material in the spring but also the length and shape of the spring. 6. The statement is false. This is because when steel and rubber of same length and cross- sectional area are subjected to same load, then the extension produced in steel is much less than that of rubber. So the ratio of stress to strain or Young’s modulus for steel is much greater than that of rubber. 7. rad/s. CBSE | Physics Sample Paper 4 Solution 8. Impulse, 21 J F t P P ? ? ? ? For the same change in momentum if t ? is increased then F decreases. If the cricketer pulls back his hands, he increases t ? , and Force on his hand decreases and he does not hurt himself. 9. Horizontal Range = Maximum height 2 2 2 sin 2 ? s in ? 2 uu gg ? tan ? =4 -1 4 ? = t a n OR No. Even though the particle is moving with constant speed along the circle, it is accelerating as its velocity continuously changes. The acceleration vector is drawn towards the centre of the circle. So as the particle moves in uniform circular motion, the acceleration vector changes direction continuously and it is not a constant vector. 10. Particle velocity is the velocity of the particles of the medium. Wave velocity is the speed at which the wave disturbance travels through the medium. 11. Let 12 mm ? 12 PP ? 2 22 12 12 12 2 ; 22 ? ?? P KE m PP KE KE mm As 1 2 1 2 and P P m m ?? Therefore KE 2 will be greater than KE 1. CBSE | Physics Sample Paper 4 Solution 12. The law of equipartition of energy states that if a system is in equilibrium at absolute temperature T, the total energy is distributed equally in different energy modes of absorption, the energy in each mode being equal to 1 . 2 B kT 13. An expansion or contraction in which no heat enters or leaves the system is called an adiabatic process. In this the temperature of the system can change. In an isothermal process, the gas expands or is compressed at constant temperature. To maintain constant temperature heat can be transferred into or out of the system. 14. Change in momentum 10 2 cos45 2 5 cos45 2 ? ? ? ? oo mv v 15. 2 1 2 mv mgh ? Dimensions of LHS are ? ? 2 1 2 2 M LT MLT ?? ? ? ? ? ? ? ? ? ? Dimension of RHS are ? ? ? ? 2 2 2 M LT L MLT ?? ? ? ? ? ? ? ? ? ? Since the dimensions of quantity on LHS is equal to the dimensions of quantity on RHS. Thus the given expression is correct. CBSE | Physics Sample Paper 4 Solution 16. The position of a particle is given by ? ? 2 ˆ ˆˆ 5 6 10 S t ti t j k ? ? ? ? ? ? ? ? ? () ˆˆ 5 12 ˆ 12 ? ? ? ?? ds t v t i t j dt dv t a t j dt ? ? ? ? 22 2 ˆˆ 1 5 12 5 12 13 / 1 12 12 / ? ? ? ? ? ? ?? ? v t i j v m s a t j a m s 17. Kinetic energy of a satellite 2 GMm E r ?? Potential energy of a satellite 2 GMm E r ? ? ? ? Total energy KE PE ?? ? ? 2 E E E ? ? ? ? ? 18. (i) A body with large reflectivity is a poor absorber. Hence it is also a poor emitter. (ii) To convert water at 100 o c to steam at 100 o c the water needs to absorb the latent heat of vaporization. So it is more efficient to use steam rather than water because when steam at 100 o c is circulated it releases latent heat in addition to heat released due to change in temperature. CBSE | Physics Sample Paper 4 Solution 19. It is a reversible engine in which all input heat originates from a hot reservoir at temperature H T and all heat rejected goes into a cold reservoir at C T , It consists of two isothermal processes and two adiabatic processes. The efficiency of a Carnot engine is 1 C H T T ??? OR The pulley system with mass m1 and m2 is shown above in fig. The tension T is same throughout.Read More

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