Science (English Medium) कक्षा ११ - CBSE Question Bank Solutions

The density of water at 0°C is 0.998 g cm^–3 and at 4°C is 1.000 g cm^–1. Calculate the average coefficient of volume expansion of water in the temperature range of 0 to 4°C.

A steel rod is clamped at its two ends and rests on a fixed horizontal base. The rod is unstrained at 20°C.
Find the longitudinal strain developed in the rod if the temperature rises to 50°C. Coefficient of linear expansion of steel = 1.2 × 10^–5 °C^–1.

Show that the moment of inertia of a solid body of any shape changes with temperature as I = I₀ (1 + 2αθ), where I₀ is the moment of inertia at 0°C and α is the coefficient of linear expansion of the solid.

A gas kept in a container of finite conductivity is suddenly compressed. The process
(a) must be very nearly adiabatic
(b) must be very nearly isothermal
(c) may be very nearly adiabatic
(d) may be very nearly isothermal

Pure water vapour is trapped in a vessel of volume 10 cm³. The relative humidity is 40%. The vapour is compressed slowly and isothermally. Find the volume of the vapour at which it will start condensing.

Answer the following question.

If `vec"v"_1 = 3hat"i" + 4hat"j" + hat"k" and vec"v"_2 = hat"i" - hat"j" - hat"k"`, determine the magnitude of `vec"v"_1 + vec"v"_2`.

Plot the corresponding reference circle for the following simple harmonic motions. Indicate the initial (t = 0) position of the particle, the radius of the circle, and the angular speed of the rotating particle. For simplicity, the sense of rotation may be fixed to be anticlockwise in every case: (x is in cm and t is in s).

x = –2 sin (3t + π/3)

Plot the corresponding reference circle for the following simple harmonic motions. Indicate the initial (t = 0) position of the particle, the radius of the circle, and the angular speed of the rotating particle. For simplicity, the sense of rotation may be fixed to be anticlockwise in every case: (x is in cm and t is in s).

x = cos `(π/6 - "t")`

Plot the corresponding reference circle for the following simple harmonic motions. Indicate the initial (t = 0) position of the particle, the radius of the circle, and the angular speed of the rotating particle. For simplicity, the sense of rotation may be fixed to be anticlockwise in every case: (x is in cm and t is in s).

x = 3 sin `(2πt + π/4)`

Which of the following measurements is most precise?

Figure shows the orientation of two vectors u and v in the XY plane.

If `u = ahati + bhatj` and `v = phati + qhatj`

which of the following is correct?

The component of a vector r along X-axis will have maximum value if ______.

A metre scale is moving with uniform velocity. This implies ______.

A cricket ball of mass 150 g has an initial velocity `u = (3hati + 4hatj)` m s⁻¹ and a final velocity `v = - (3hati + 4hatj)` m s⁻¹ after being hit. The change in momentum (final momentum-initial momentum) is (in kg m s¹)

In the previous problem (5.3), the magnitude of the momentum transferred during the hit is ______.

A hockey player is moving northward and suddenly turns westward with the same speed to avoid an opponent. The force that acts on the player is ______.

A body of mass 2 kg travels according to the law x(t) = pt + qt² + rt³ where p = 3 ms⁻¹, q = 4 ms⁻² and r = 5 ms⁻³. The force acting on the body at t = 2 seconds is ______.

The motion of a particle of mass m is given by x = 0 for t < 0 s, x(t) = A sin 4 pt for 0 < t < (1/4) s (A > o), and x = 0 for t > (1/4) s. Which of the following statements is true?

1. The force at t = (1/8) s on the particle is – 16π² Am.
2. The particle is acted upon by on impulse of magnitude 4π² A m at t = 0 s and t = (1/4) s.
3. The particle is not acted upon by any force.
4. The particle is not acted upon by a constant force.
5. There is no impulse acting on the particle.

The position time graph of a body of mass 2 kg is as given in figure. What is the impulse on the body at t = 0 s and t = 4 s.

Why does a child feel more pain when she falls down on a hard cement floor, than when she falls on the soft muddy ground in the garden?