HSC Science (General) १२ वीं कक्षा - Maharashtra State Board Important Questions

A soap bubble of radius 12 cm is blown. Surface tension of soap solution is 30 dyne/cm. Calculate the work done in blowing the soap bubble.

In a conical pendulum, a string of length 120 cm is fixed at rigid support and carries a mass
of 150 g at its free end. If the mass is revolved in a horizontal circle of radius 0.2 m around a
vertical axis, calculate tension in the string (g = 9.8 m/s²)

A body weighs 4.0 kg-wt on the surface of the Earth. What will be its weight on the surface of a plant whose mass is `1/8` th of the mass of the Earth and radius half `(1/2)` of that of the Earth?

Show that the surface tension of a liquid is numerically equal to the surface energy per unit
area.

A big drop of radius R is formed from 1000 droplets of water. The radius of a droplet will be _______

A) 10 R

B) R/10

C) R/100

D) R/1000

Apparent frequency of the sound heard by a listener is less than the actual frequency of sound emitted by source. In this case _______.

(A) listener moves towards source

(B) source moves towards listener

(C) listener moves away from the source.

(D) source and listener move towards each other.

State any two characteristics of the angle of contact

Show that only odd harmonics are present in an air column vibrating in a pipe closed at one end.

A stretched wire emits a fundamental note of frequency 256 Hz. Keeping the stretching force constant and reducing the length of wire by 10 cm, the frequency becomes 320 Hz. Calculate the original length of wire.

State any four applications of Doppler effect

Calculate the work done in increasing the radius of a soap bubble in air from 1 cm to 2 cm. The surface tension of soap solution is 30 dyne/cm. (Π = 3.142).

What is meant by harmonics?

Show that only odd harmonics are present as overtones in the case of an air column vibrating in a pipe closed at one end.

When a sparingly soluble substance like alcohol is dissolved in water, surface tension of water

Obtain an expression for the rise of a liquid in a capillary tube.

Show that even as well as odd harmonics are present as overtones in the case of an air column vibrating in a pipe open at both the ends.

A wheel of moment of inertia 1 kg.m² is rotating at a speed of 30 rad/s. Due to friction on the axis, it comes to rest in 10 minutes. Calculate the average torque of the friction.

Choose the correct option:

A standing wave is produced on a string clamped at one end and free at the other. The length of the string ______.

The energy stored in a soap bubble of diameter 6 cm and T = 0.04 N/m is nearly ______.

Why is the surface tension of paints and lubricating oils kept low?