HSC Science (General) 11th Standard - Maharashtra State Board Question Bank Solutions for Physics

Two copper spheres of radii 6 cm and 12 cm respectively are suspended in an evacuated enclosure. Each of them are at a temperature 15°C above the surroundings. The ratio of their rate of loss of heat is.................

1. 2:1
2. 1:4
3. 1:8
4. 8:1

The dimensions of emissive power are

A pinhole is made in a hollow sphere of radius 5 cm whose inner wall is at temperature 727^oC. Find the power radiated per unit area. [Stefan’s constant σ = 5.7 x 10^-8 J/m² s K4 , emissivity (e) = 0.2]

Compute the temperature at which the r.m.s. speed of nitrogen molecules is 832 m/s. [Universal gas constant, R = 8320 J/k mole K, molecular weight of nitrogen = 28.]

The light from the Sun is found to have a maximum intensity near the wavelength of 470 nm. Assuming the surface of the Sun as a black body, the temperature of the Sun is _____________.

[Wien's constant b = 2 .898 x l0^{- 3}mK]

A metal ball cools from 64 ^°C to 50 ^°C in 10 minutes and to 42 ^°C in next 10 minutes. The ratio of rates of fall of temperature during the two intervals is _______.

The susceptibility of magnesium at 300 K is 2.4 x 10^-5. At what temperature will the susceptibility increase to 3.6 x 10^-5?

Give a reason for the following:

Long-distance radio broadcasts use short-wave bands. Why?

Give a reason for the following:

It is necessary to use satellites for long-distance TV transmission. Why?

1000 tiny mercury droplets coalesce to form a bigger drop. In this process, temperature of the drop _______ .

(A) increases

(B) may increase or decrease

(C) decreases

(D) does not change

A body cools from 62°C to 54°C in 10 minutes and to 48°C in the next 10 minutes. Find the temperature of the surroundings.

The susceptibility of magnesium at 300K is 1.2 x 10^-5. At what temperature will the susceptibility increase to 1.8 X 10^-5?

The substance which allows heat radiations to pass through is _______.

(A) iron

(B) water vapour

(C) wood

(D) dry air

Choose the correct option.

Which of the following is not a fundamental unit?

Show that vectors `vec"a" = 2hat"i" + 3hat"j" + 6hat"k", vec"b" = 3hat"i" - 6hat"j" + 2hat"k" and vec"c" = 6hat"i" + 2hat"j" - 3hat"k"` are mutually perpendicular.

Determine the vector product of `vec"v"_1 = 2hat"i" + 3hat"j" - hat"k" and vec"v"_2 = hat"i" + 2hat"j" - 3hat"k"`

Solve the following problem.

Given `vec"v"_1 = 5hat"i" + 2hat"j" and vec"v"_2 = "a"hat"i" - 6hat"j"` are perpendicular to each other, determine the value of a.

Answer the following question.

Define average velocity and instantaneous velocity. When are they same?

Define the following term:

Free fall

Answer the following question.

If the motion of an object is described by x = f(t), write formulae for instantaneous velocity and acceleration.