Science (English Medium) इयत्ता ११ - CBSE Question Bank Solutions for Physics

If p₀ = 1.03 × 10⁵ Nm^–2, ρ₀ = 1.29 kg m^–3 and g = 9.8 ms^–2, at what height will the pressure drop to (1/10) the value at the surface of the earth?

Mark the correct options:

1. A system X is in thermal equilibrium with Y but not with Z. System Y and Z may be in thermal equilibrium with each other.
2. A system X is in thermal equilibrium with Y but not with Z. Systems Y and Z are not in thermal equilibrium with each other.
3. A system X is neither in thermal equilibrium with Y nor with Z. The systems Y and Z must be in thermal equilibrium with each other.
4. A system X is neither in thermal equilibrium with Y nor with Z. The system Y and Z may be in thermal equilibrium with each other.

During summers in India, one of the common practice to keep cool is to make ice balls of crushed ice, dip it in flavoured sugar syrup and sip it. For this a stick is inserted into crushed ice and is squeezed in the palm to make it into the ball. Equivalently in winter, in those areas where it snows, people make snow balls and throw around. Explain the formation of ball out of crushed ice or snow in the light of P–T diagram of water.

100 g of water is supercooled to –10°C. At this point, due to some disturbance mechanised or otherwise some of it suddenly freezes to ice. What will be the temperature of the resultant mixture and how much mass would freeze?

`[S_w = 1cal/g/^circC and L_(Fusion)^w = 80cal/g]`

Consider P-V diagram for an ideal gas shown in figure.

Out of the following diagrams (figure), which represents the T-P diagram?

(i)	(ii)
(iii)	(iv)

A gas mixture consists of 2.0 moles of oxygen and 4.0 moles of neon at temperature T. Neglecting all vibrational modes, calculate the total internal energy of the system. (Oxygen has two rotational modes.)

Explain why there is fall in temperature with altitude.

The relation between acceleration and displacement of four particles are given below: Which one of the particles is executing simple harmonic motion?

A particle executing S.H.M. has a maximum speed of 30 cm/s and a maximum acceleration of 60 cm/s². The period of oscillation is ______.

Which of the following statements is/are true for a simple harmonic oscillator?

1. Force acting is directly proportional to displacement from the mean position and opposite to it.
2. Motion is periodic.
3. Acceleration of the oscillator is constant.
4. The velocity is periodic.

Two identical springs of spring constant K are attached to a block of mass m and to fixed supports as shown in figure. When the mass is displaced from equilibrium position by a distance x towards right, find the restoring force

When will the motion of a simple pendulum be simple harmonic?

The length of a second’s pendulum on the surface of earth is 1 m. What will be the length of a second’s pendulum on the moon?

Find the time period of mass M when displaced from its equilibrium position and then released for the system shown in figure.

A body of mass m is situated in a potential field U(x) = U₀ (1 – cos αx) when U₀ and α are constants. Find the time period of small oscillations.

Consider a pair of identical pendulums, which oscillate with equal amplitude independently such that when one pendulum is at its extreme position making an angle of 2° to the right with the vertical, the other pendulum makes an angle of 1° to the left of the vertical. What is the phase difference between the pendulums?

A cylindrical log of wood of height h and area of cross-section A floats in water. It is pressed and then released. Show that the log would execute S.H.M. with a time period. `T = 2πsqrt(m/(Apg))` where m is mass of the body and ρ is density of the liquid.

A tunnel is dug through the centre of the Earth. Show that a body of mass ‘m’ when dropped from rest from one end of the tunnel will execute simple harmonic motion.

A simple pendulum of time period 1s and length l is hung from a fixed support at O, such that the bob is at a distance H vertically above A on the ground (Figure). The amplitude is θ₀. The string snaps at θ = θ₀/2. Find the time taken by the bob to hit the ground. Also find distance from A where bob hits the ground. Assume θ_o to be small so that sin θ_o = θ_o and cos θ_o = 1.

A tuning fork A, marked 512 Hz, produces 5 beats per second, where sounded with another unmarked tuning fork B. If B is loaded with wax the number of beats is again 5 per second. What is the frequency of the tuning fork B when not loaded?