CBSE 11TH PHYSICS - Online Test
Q1. Two match sticks are laid side by side on the surface of water. When a drop of light oil on the end of a third match stick is touched to the surface film between the two floating sticks, the two match sticks
Answer : Option D
Explaination / Solution:
No Explaination.
Q2. for motion under an external conservative force
Answer : Option D
Explaination / Solution:
Mechanical energy is the sum of the potential and kinetic energies in a system. The principle of the conservation of mechanical energy states that the total mechanical energy in a system (i.e., the sum of the potential and kinetic energies) remains constant as long as the only forces acting are conservative forces.
Q3. A house has well-insulated walls. It contains a volume of 100 of air at 300 K. Calculate the energy required to increase the temperature of this air by 1.00C.
Answer : Option A
Explaination / Solution:
Q=nCPΔT=72RnΔT=72(PVT)ΔTQ=72×(1.01×105×100300)×1=118KJ
Q4. A student eats a dinner rated at 2000 Calories. He wishes to do an equivalent amount of work in the gymnasium by lifting a 50.0-kg barbell. How many times must he raise the barbell to expend this much energy? Assume that he raises the barbell 2.00 m each time he lifts it and that he regains no energy when he drops the barbell to the floor.
Answer : Option D
Explaination / Solution:
Total no.of times he lift barbell = Total energy / energy in lifting barbell once
Q5. One mole of an ideal gas at standard temperature and pressure occupies 22.4 L (molar volume). What is the ratio of molar volume to the atomic volume of a mole of hydrogen? (Take the size of hydrogen molecule to be about 1 Å).
Answer : Option D
Explaination / Solution:
Radius of hydrogen atom, r = 0.5 = 0.5 × 10–10 m
Volume of hydrogen atom =
=
Now, 1 mole of hydrogen contains 6.023 × 1023 hydrogen atoms.
Volume of 1 mole of hydrogen atoms, Va = 6.023 × 1023 × 0.524 × 10–30
= 3.16 × 10–7 m3
Molar volume of 1 mole of hydrogen atoms at STP,
Vm = 22.4 L = 22.4 × 10–3 m3
=> = 7.08
=
Q6. A particle is oscillating according to the equation X=7 cos 0.5 πt, where t is in seconds. The point moves from the position of equilibrium to maximum displacement in time
Answer : Option B
Explaination / Solution:
No Explaination.
Q7.
A stone thrown from the top of a building is given an initial velocity of 20.0 m/s straight upward. Determine the velocity in m/sec when the stone returns to the height from which it was thrown. g =9.8 m /
Answer : Option D
Explaination / Solution:
we get
As the motion of the stone is downward, and the”+”sign was assigned for the upward motion,
we get for vC = −vA= −20 m/s.
Q8. Longitudinal waves cannot be propagated through
Answer : Option A
Explaination / Solution:
No Explaination.
Q9. Vectors can be added by
Answer : Option B
Explaination / Solution:
Parallelogram law of vector addition is,If two vectors are considered to be the adjacent sides of a Parallelogram, then the resultant of two vectors is given by the vector which is a diagonal passing through the point of contact of two vectors.
Q10. What is the density of water at a depth where pressure is 80.0 atm, given that its density at the surface is 1.03 kg ?
Answer : Option A
Explaination / Solution:
No Explaination.
