CBSE 11TH PHYSICS - Online Test
Q1. A new unit of length is chosen such that the speed of light in vacuum is unity. What is the distance between the Sun and the Earth in terms of the new unit if light takes 8 min and 20 s to cover this distance?
Answer : Option D
Explaination / Solution:
Distance between the Sun and the Earth = Speed of light ×Time taken by light to cover the distance
Given that in the new unit,
speed of light = 1 unit
Time taken, t = 8 min 20 s = 500 s Distance between the Sun and the Earth = 1 x 500 = 500 units
Q2. In the arrangement shown in the figure, if the block of mass m is displaced, the frequency is given by
Answer : Option A
Explaination / Solution:
No Explaination.
Q3. A truck is coming towards you from a distance of 1000m on a straight road, at time t=0. The driver stops for a second near a poster. He reaches you in 100 sec. The average speed in m/s is
Answer : Option A
Explaination / Solution:
Total distance covered s = 1000 m
Total time taken t = 100-0 = 100 s
Average speed
Q4. The velocity of sound in gas in which two waves of wavelength 1.0 m and 0.01 m produces 4 beats/sec. is
Answer : Option D
Explaination / Solution:
No Explaination.
Q5. An aircraft executes a horizontal loop of radius 1.00 km with a steady speed of 900 km/h. Compare its centripetal acceleration with the acceleration due to gravity.
Answer : Option B
Explaination / Solution:
Radius of the loop, r = 1 km = 1000 m
Speed of the aircraft, v = 900 km/h
=
Centripetal acceleration,
=
Acceleration due to gravity, g = 9.8 m/s2
= 6.4 g
Q6. Two wires of diameter 0.25 cm, one made of steel and the other made of brass are loaded as shown in Figure The unloaded length of steel wire is 1.5 m and that of brass wire is 1.0 m. Compute the elongation of the steel wire.
Answer : Option C
Explaination / Solution:
No Explaination.
Q7. Two cylinders A and B of equal capacity are connected to each other via a stopcock. A contains a gas at standard temperature and pressure. B is completely evacuated. The entire system is thermally insulated. The stopcock is suddenly opened. Do the intermediate states of the system (before settling to the final equilibrium state) lie on its P-V-T surface?
Answer : Option C
Explaination / Solution:
Pressure and volume will be changed.
Q8.
A truck starts from rest and accelerates uniformly at 2.0 m . At t = 10 s, a stone is dropped by a person standing on the top of the truck (6 m high from the ground). What is the magnitude of velocity (in m ) of the stone at t = 11s? (Neglect air resistance.)
Answer : Option C
Explaination / Solution:
During first 10 , the horizontal component of the velocity is vx = u + at = 0+2x10 = 20 m/s
From 10 to 11 s, the vertical component of the velocity is vy=u + gt = 0 + 10x1 = 10m/s
Relative velocity is,
Q9. A 6.0-kg block initially at rest is pulled to the right along a horizontal frictionless surface by a constant horizontal force of 12 N. Find the speed of the block after it has moved 3.0 m.
Answer : Option B
Explaination / Solution:
from work kinetic energy theorm
ΔK=W12mv2−12mu2=Fs(12×6×v2)−0=12×33v2=36v2=12v=3.5m/sec
Q10. The major contribution of S.N. Bose was in
Answer : Option D
Explaination / Solution:
Satyendra Nath Bose was an Indian physicist from Bengal specialising in theoretical physics. He is best known for his work on quantum mechanics in the early 1920s, providing the foundation for Bose–Einstein statistics and the theory of the Bose–Einstein condensate.
