Practice Questions

Q5. The time period of a satellite in a circular orbit of the radius R is T. The period of another satellite in a circular orbit of the radius 9R is: (1) 9T (2) 27T (3) 12T (4) 3T

Q5. The instantaneous velocity of a particle moving in a straight line is given as v = αt + βt2 , where α and β are constants. The distance travelled by the particle between 1 s and 2 s is: (1) 3α + 7β (2) 32 α + 73 β (3) α 2 + β3 (4) 32 α + 72 β Q6. → A force F = + N acts on a body of mass 5 kg. If the body starts from rest, its position vector →rat (40ˆi 10ˆj) time t = 10 s will be + + m (1) (100ˆi 400ˆj) m (2) (100ˆi 100ˆj) + + m (3) (400ˆi 100ˆj) m (4) (400ˆi 400ˆj)

Q5. A bomb is dropped by a fighter plane flying horizontally. To an observer sitting in the plane, the trajectory of the bomb is a : (1) straight line vertically down the plane (2) parabola in a direction opposite to the motion of plane (3) parabola in the direction of motion of plane (4) hyperbola

Q5. Angular momentum of a single particle moving with constant speed along circular path : (1) remains same in magnitude but changes in the (2) remains same in magnitude and direction direction (3) is zero (4) changes in magnitude but remains same in the direction

Q5. If the kinetic energy of a moving body becomes four times its initial kinetic energy, then the percentage change in its momentum will be: (1) 100% (2) 200% (3) 300% (4) 400%

Q6. On the basis of kinetic theory of gases, the gas exerts pressure because its molecules: (1) continuously stick to the walls of container. (2) suffer change in momentum when impinge on the walls of container. (3) continuously lose their energy till it reaches wall. (4) are attracted by the walls of container.

Q6. A bimetallic strip consists of metals A and B. It is mounted rigidly as shown. The metal A has higher coefficient of expansion compared to that of metal B. When the bimetallic strip is placed in a cold both, it will : (1) Bend towards the right (2) Not bend but shrink (3) Neither bend nor shrink (4) Bend towards the left

Q6. A planet revolving in elliptical orbit has : A. a constant velocity of revolution. B. has the least velocity when it is nearest to the sun. C. its areal velocity is directly proportional to its velocity. D. areal velocity is inversely proportional to its velocity. E. to follow a trajectory such that the areal velocity is constant. Choose the correct answer from the options given below: (1) A only (2) C only (3) E only (4) D only

Q6. Two identical springs of spring constant 2k are attached to a block of mass m and to fixed support (see figure). When the mass is displaced from equilibrium position on either side, it executes simple harmonic motion. The time period of oscillations of this system is : (1) π√mk (2) 2π√m2k (3) π√m2k (4) 2π√mk

Q7. The amount of heat needed to raise the temperature of 4 moles of a rigid diatomic gas from 0 °C to 50 °C when no work is done is (R is the universal gas constant) (1) 250R (2) 750R (3) 175R (4) 500R

Q7. What will be the average value of energy for a monoatomic gas in thermal equilibrium at temperature T? (1) 2 3 kBT (2) kBT (3) 2 3 kBT (4) 21 kBT

Q7. Two identical metal wires of thermal conductivities K1 and K2 respectively are connected in series. The effective thermal conductivity of the combination is: (1) 2 K1 K2 (2) K1+K2 K1+K2 2 K1 K2 (3) K1+K2 (4) K1 K2 K1 K2 K1+K2

Q7. Two different metal bodies 𝐴 and 𝐵 of equal mass are heated at a uniform rate under similar conditions. The variation of temperature of the bodies is graphically represented as shown in the figure. The ratio of specific heat capacities is: JEE Main 2021 (25 Jul Shift 1) JEE Main Previous Year Paper 8 3 (1) (2) 3 8 (3) 3 (4) 4 4 3

Q7. The angular momentum of a planet of mass M moving around the sun in an elliptical orbit is L. The magnitude of the areal velocity of the planet is : JEE Main 2021 (18 Mar Shift 2) JEE Main Previous Year Paper (1) 4L (2) L M M (3) 2L (4) L M 2M

Q7. What will be the average value of energy along one degree of freedom for an ideal gas in thermal equilibrium at a temperature T ? ( kB is Boltzmann constant) (1) 2 1 kBT (2) 32 kBT (3) 3 kBT (4) kBT 2

Q7. The R.M.S. speeds of the molecules of Hydrogen, Oxygen, and Carbon dioxide at the same temperature are vH, vO and vC respectively, then: (1) vC > vO > vH (2) vH = vO > vC (3) vH > vO > vC (4) vH = vO = vC

Q7. In thermodynamics, heat and work are : (1) Path functions (2) Intensive thermodynamic state variables (3) Extensive thermodynamic state variables (4) Point functions

Q8. T0 is the time period of a simple pendulum at a place. If the length of the pendulum is reduced to 161 times of its initial value, the modified time period is (1) T0 (2) 8πT0 (3) 4T0 (4) 14 T0

Q8. Each side of a box made of metal sheet in cubic shape is 𝑎 at room temperature 𝑇, the coefficient of linear expansion of the metal sheet is 𝛼. The metal sheet is heated uniformly, by a small temperature 𝛥𝑇, so that its new temperature is 𝑇+ 𝛥𝑇. Calculate the increase in the volume of the metal box. (1) 4𝑎3𝛼𝛥𝑇 (2) 3𝑎3𝛼𝛥𝑇 (3) 4𝜋𝑎3𝛼𝛥𝑇 (4) 43𝜋𝑎3𝛼𝛥𝑇

Q8. When a particle executes SHM, the nature of graphical representation of velocity as a function of displacement is: (1) straight line (2) elliptical (3) circular (4) parabolic

Q8. The volume V of an enclosure contains a mixture of three gases, 16 g of oxygen, 28 g of nitrogen and 44 g of carbon dioxide at absolute temperature T . Consider R as universal gas constant. The pressure of the mixture of gases is : (1) 88RT (2) 3RT V V (3) 5 RT (4) 4RT 2 V V

Q9. If the time period of a two meter long simple pendulum is 2 s, the acceleration due to gravity at the place where pendulum is executing S.H.M. is: (1) 2π2 m s−2 (2) 16 m s−2 (3) π2 m s−2 (4) 9. 8 m s−2

Q9. Which of the following equations represents a travelling wave? (1) y = A sin(15x −2t) (2) y =Aex cos(ωt −θ) (3) y = Ae−x2(vt + θ) (4) y = A sin x cos ωt

Q9. For a gas 𝐶P - 𝐶V = 𝑅 in a state 𝑃 and 𝐶P - 𝐶V = 1 . 10𝑅 in a state 𝑄, 𝑇P and 𝑇Q are the temperatures in two different states 𝑃 and 𝑄, respectively. Then (1) 𝑇P = 𝑇Q (2) 𝑇P < 𝑇Q (3) 𝑇P = 0 . 9𝑇Q (4) 𝑇P > 𝑇Q

Q9. An ideal gas in a cylinder is separated by a piston in such a way that the entropy of one part is S1 and that of the other part is S2 . Given that S1 > S2 . If the piston is removed then the total entropy of the system will be: (1) S1 × S2 (2) S1 −S2 (3) S1 (4) S1 + S2 S2