CBSE 11TH PHYSICS - Online Test
Q1. In a completely inelastic collision
Answer : Option A
Explaination / Solution:
For perfectly Inelastic collision coefficient of restitution is zero.
coefficient of restitution e= relative velocity of separation / relative velocity of approach
e = 0
so that relative velocity of separation will be zero means the colliding bodies stick together and move as one body after the collision
Q2. Columns are loaded in
Answer : Option B
Explaination / Solution:
No Explaination.
Q3. The spontaneous processes of nature are
Answer : Option B
Explaination / Solution:
Spontaneous processes are irreversible because they can be reversed only by taking a different path to get back to their original state. A reversible process can take the same path to return to its original state.
Q4. A pebble of mass 0.05 kg is thrown vertically upwards. Give the direction and magnitude of the net force on the pebble, if the pebble was thrown at an angle of 45° with the horizontal direction, Ignore air resistance
Answer : Option B
Explaination / Solution:
F = mg = 0.05 x 10 = 0.5 N. The horizontal component of the velocity remain constant.
Q5. Postulates are
Answer : Option D
Explaination / Solution:
A postulate is an assumption, that is, a proposition or statement, that is assumed to be true without any proof. Postulates are the fundamental propositions used to prove other statements known as theorems. Once a theorem has been proven it is may be used in the proof of other theorems.
Q6. Angular momentum of a body is defined as the product of
Answer : Option A
Explaination / Solution:
if r is perpendicular to p (in case of circular motion)
L = mvr
Q7. If a film of width L is stretched in the longitudinal direction a distance d by force F, surface tension is given by
Answer : Option C
Explaination / Solution:
Let L be the width of the film. Since the film has two surfaces, the total length along which the surface force acts on the slider is 2L. The surface tension S in the film is defined as the ratio of the surface force F to the length d (perpendicular to the force) along which the force acts
S=F/d
Hence, in the case, d = 2L
S=F/2L
Q8.
Estimate the total number of air molecules (inclusive of oxygen, nitrogen, water vapor and other constituents) in a room of capacity 25.0 at a temperature of 27 C and 1 atm pressure.
Answer : Option D
Explaination / Solution:
PV=NkTN=PVkT=1.01×105×251.38×10−23×300=6.1×1026
Q9. If is the temperature of the surrounding medium and is the temperature of the body, then according to Newton’s Law of Cooling rate of cooling of the body is
Answer : Option B
Explaination / Solution:
Newton's law of cooling states that the rate of heat loss of a body is directly proportional to the difference in the temperatures between the body and its surroundings.
Q10. Electric charge is expressed in SI units as
Answer : Option B
Explaination / Solution:
The SI derived unit of electric charge is the coulomb (C). The symbol Q often denotes charge.
