Science (English Medium) Class 11 - CBSE Question Bank Solutions for Physics

A railway track (made of iron) is laid in winter when the average temperature is 18°C. The track consists of sections of 12.0 m placed one after the other. How much gap should be left between two such sections, so that there is no compression during summer when the maximum temperature rises to 48°C? Coefficient of linear expansion of iron = 11 × 10^–6 °C^–1.

A circular hole of diameter 2.00 cm is made in an aluminium plate at 0°C. What will be the diameter at 100°C? α for aluminium = 2.3 ×  10^–5 °C^–1.

A pendulum clock shows correct time at 20°C at a place where g = 9.800 m s^–2. The pendulum consists of a light steel rod connected to a heavy ball. It is taken to a different place where g = 9.788 m s^–1. At what temperature will the clock show correct time? Coefficient of linear expansion of steel = 12 × 10^–6 °C^–1.

The volume of a glass vessel is 1000 cc at 20°C. What volume of mercury should be poured into it at this temperature so that the volume of the remaining space does not change with temperature? Coefficients of cubical expansion of mercury and glass are 1.8 × 10^–6 °C^–1 and 9.0 × 10^–6 °C^–1 , respectively.

The densities of wood  and benzene at 0°C are 880 kg m³ and 900 kg m^–3 , respectively. The coefficients of volume expansion are 1.2 × 10^–3 °C^–1 for wood and 1.5 × 10^–3 °C^–1for benzene. At what temperature will a piece of wood just sink in benzene?

A steel rod of length 1 m rests on a smooth horizontal base. If it is heated from 0°C to 100°C, what is the longitudinal strain developed?

A steel wire of cross-sectional area 0.5 mm² is held between two fixed supports. If the wire is just taut at 20°C, determine the tension when the temperature falls to 0°C. Coefficient of linear expansion of steel is 1.2 × 10^–5 °C^–1 and its Young's modulus is 2.0 × 10^–11 Nm^–2.

A steel ball that is initially at a pressure of 1.0 × 10⁵ Pa is heated from 20°C to 120°C, keeping its volume constant.
Find the pressure inside the ball. Coefficient of linear expansion of steel = 12 × 10^–6 °C^–1and bulk modulus of steel = 1.6 × 10¹¹ Nm^–2.

Which of the following example represent periodic motion?

A swimmer completing one (return) trip from one bank of a river to the other and back.

Which of the following example represent periodic motion?

A freely suspended bar magnet displaced from its N-S direction and released.

Which of the following example represent periodic motion?

A hydrogen molecule rotating about its center of mass.

Which of the following example represent (nearly) simple harmonic motion and which represent periodic but not simple harmonic motion?

The rotation of the earth about its axis.

Which of the following example represent (nearly) simple harmonic motion and which represent periodic but not simple harmonic motion?

A motion of an oscillating mercury column in a U-tube.

Which of the following example represent (nearly) simple harmonic motion and which represent periodic but not simple harmonic motion?

The motion of a ball bearing inside a smooth curved bowl, when released from a point slightly above the lowermost point.

Given below are some functions of x and t to represent the displacement (transverse or longitudinal) of an elastic wave. State which of these represent (i) a traveling wave, (ii) a stationary wave or (iii) none at all:

y = 2 cos (3x) sin (10t)

Given below are some functions of x and t to represent the displacement (transverse or longitudinal) of an elastic wave. State which of these represent (i) a traveling wave, (ii) a stationary wave or (iii) none at all:

`"y" = 2sqrt(x - "vt")`

Given below are some functions of x and t to represent the displacement (transverse or longitudinal) of an elastic wave. State which of these represent (i) a traveling wave, (ii) a stationary wave or (iii) none at all:

y = 3 sin (5x – 0.5t) + 4 cos (5x – 0.5t)

The radius of atom is of the order of 1 Å and the radius of nucleus is of the order of fermi. How many magnitudes higher is the volume of atom as compared to the volume of nucleus?

1. The earth-moon distance is about 60 earth radius. What will be the diameter of the earth (approximately in degrees) as seen from the moon?
2. Moon is seen to be of (½)°diameter from the earth. What must be the relative size compared to the earth?
3. From parallax measurement, the sun is found to be at a distance of about 400 times the earth-moon distance. Estimate the ratio of sun-earth diameters.

The distance of a galaxy is of the order of 10²⁵ m. Calculate the order of magnitude of time taken by light to reach us from the galaxy.