CBSE Class 11 Physics MCQs Set 13

Question. Maximum reinforcement of two waves is obtained at points with phase difference of...
(a) nπ
(b) nπ/2
(c) 2nπ
(d) (2n + 1)π/2

Answer : C

Question. If 'd' is the width of slit, the diffraction is greater for...
(a) larger d, larger λ
(b) larger d, smaller λ
(c) smaller d, larger λ
(d) smaller d, smaller λ

Answer : C

Question. The SI unit of Planck's constant is...
(a) J
(b) J/s
(c) J.s
(d) J/s.K

Answer : B

Question. The energy of an electron depends on...
(a) its distance from the nucleus
(b) the diameter of the nucleus
(c) its diameter
(d) its charge

Answer : A

Question. Which of the following is not the spectral series obtained in the hydrogen spectrum?
(a) Balmer series
(b) Pascal series
(c) Pfund series
(d) Paschen series

Answer : B

Question. The conductivity of a semiconductor can be changed by adding impurities and by...
(a) changing its size
(b) changing its shape
(c) changing its density
(d) irradiation

Answer : D

Question. A body falling from rest covers a distance h/2 in the last second of its fall. Then the height h from which it falls is...
(a) 9.8 m
(b) 58.28 m
(c) 100/√ 2 m
(d) 50/√ 2 m

Answer : B

Question. The two ends of a train moving with uniform acceleration pass a certain point with velocities v₁ and v₂. The velocity with which the middle point of the train passes the same point is...
(a) √(v₁² + v₂²)/2
(b) √(v₁² - v₂²)/2
(c) √(v₂² - v₁²)/2
(d) (v₁ + v₂)/2

Answer : A

Question. The angle which the vector 3i + 4j makes with X-axis is...
(a) 30°
(b) 45°
(c) tan-1 (4/3)
(d) tan^-1 (3/4)

Answer : D

Question. Two bodies of equal mass are in uniform circular motion with the same period.If r₁ and r₂ are the radii of their circular paths then the ratio of their centripetal force is...
(a) r₁² / r²₂
(b) r²₂ / r¹₂
(c) r₁ / r₂
(d) r₂/ r₁

Answer : D

Question. A ball is dropped from a vertical height 'h' on the ground. If 'e' is the coefficient of restitution then the height to which the ball goes up after it rebounds for n-th time is...
(a) h/(eⁿ)
(b) h/(e²ⁿ)
(c) h.(eⁿ)
(d) h.(e²ⁿ)

Answer : D

Question. Water falls on the blades of a turbine at the rate of 10 kg/s from a height of 10 m. The power delivered to the turbine is...(take g = 10 m/s²)
(a) 1 W
(b) 1 kW
(c) 100 W
(d) 100 kW

Answer : B

Question. An electric fan has a blade of length l. The fan makes n rotations in one minute. The acceleration of a point on the tip of the blade is...
(a) 4π².l/n
(b) 4π².l.n²/(60 x 60)
(c) 4π².l.n²/60
(d) 4π².l/60n

Answer : B

Question. A body of mass m slides down an incline and reaches the bottom with velocity v. If a ring of same mass rolls down the same incline then the velocity of the ring at the bottom is...
(a) v
(b) 2v
(c) v/√ 2
(d) (√ 2)v

Answer : D

Question. The gravitational force between two particles of mass 2 kg each separated by a distance 2m is...
(a) 6.67 x 10^-11 N
(b) 0
(c) 3.335 x 10^-11 N
(d) 13.34 x 10^-11 N

Answer : A

Question. The period of revolution of a satellite in a circular orbit of radius r is T. The period of the same satellite in another circular orbit of radius 4r is...
(a) T/4
(b) T/8
(c) 2T
(d) 8T

Answer : D

Question. If K is Boltzmann's constant, the average kinetic energy of a molecule of a perfect gas is...
(a) 2/3 kT
(b) 2.5 kT
(c) 3.5 kT
(d) 1.5 kT

Answer : D

Question. The efficiency of a Carnot engine working between constant high temperature T₁ and constant low temperature T₂ is maximum when...
(a) T₁ and T₂ are high
(b) T₁ is high and T₂ is low
(c) T₂ is high and T₁ is low
(d) T₁ and T₂ equal

Answer : B

Question. A cooking vessel must have...
(a) high thermal conductivity and high specific heat
(b) low thermal conductivity and low specific heat
(c) high thermal conductivity and low specific heat
(d) low thermal conductivity and high specific heat

Answer : C

Question. The total energy of a particle executing SHM is 100 J.Then the maximum value of kinetic energy is...
(a) 50 J
(b) 100 J
(c) 25 J
(d) 10 J

Answer : B

Question. When a mass m is suspended from a spring its period of oscillation is one second. If the mass is reduced to m/2, the new period will be...
(a) 1 second
(b) 1/2 second
(c) √ 2 second
(d) 1/(√ 2) second

Answer : D

Question. Which of the following quantities can be considered as the fundamental quantity of a wave?
(a) Velocity
(b) Frequency
(c) Wavelength
(d) Amplitude

Answer : B

Question. In a stationary wave, strain is...
(a) maximum at node
(b) maximum at antinode
(c) minimum at node
(d) equal at nodes and antinodes

Answer : A

Question. Dimensions of momentum are...
(a) M¹L¹T¹
(b) M¹L¹T^-2
(c) M¹L^-1T^-2
(d) M¹L^-1T^-1

Answer : A

Question. When a 1-N force acts on a 1-N object that is able to move freely, the object receives...
(a) a speed of 1 m/s
(b) an acceleration of 1.02 m/s²
(c) an acceleration of 1 m/s²
(d) an acceleration of 9.8 m/s²

Answer : D

Question. The coefficient of static friction for steel on ice is...
(a) 0.1
(b) 0.1 N
(c) 0.1 Nm
(d) 0.1 N.kg^-1

Answer : A

Question. The work done in moving an object from A to B against a non-conservative force
(a) cannot be recovered by moving it from B to A
(b) does not depend on the path taken between A and B
(c) is always entirely converted in to heat
(d) disappears forever

Answer : A

Question. Car A has mass of 1000 kg and speed of 60 kmph. Car B has mass of 2000 kg and speed of 30 kmph. The kinetic energy of car A is...
(a) half that of car B
(b) equal to that of car B
(c) twice that of car B
(d) four times that of car B

Answer : C

Question. Brownian motion increases as...
(a) the particle size increases
(b) the viscosity of the medium increases
(c) the temperature increases
(d) the temperature decreases

Answer : C

Question. The equilibrium separation between the molecules corresponds to...
(a) maximum potential energy
(b) minimum potential energy
(c) zero potential energy
(d) zero kinetic energy

Answer : B