HSC Science (Electronics) 12th Standard Board Exam - Maharashtra State Board Question Bank Solutions

Derive the relation between surface tension and surface energy per unit area.

With a neat labelled diagram, show that all harmonics are present in an air column contained in a pipe open at both the ends. Define end correction.

A pipe which is open at both ends is 47 cm long and has an inner diameter 5 cm. If the speed of sound in air is 348 m/s, calculate the fundamental frequency of air column in that pipe.

A pipe open at both ends resonates to a frequency ‘n₁’ and a pipe closed at one end resonates to a frequency ‘n₂’. If they are joined to form a pipe closed at one end, then the fundamental frequency will be ______.

(A)  `(n_1n_2)/(2n_2+n_1)`

(B) `(2n_2n_1)/(2n_2+n_1)`

(C) `(2n_2n_1)/(n_1+n_2)`

(D) `(n_2+2n_1)/(n_1n_2)` 

Two sound notes have wavelengths 83/170 m and 83/172 m in the air. These notes when sounded together produce 8 beats per second. Calculate the velocity of sound in the air and frequencies of the two notes.

Explain self induction and mutual induction

Discuss different modes of vibrations in an air column of a pipe open at both the ends.

State the cause of end correction.

Find the end correction for the pipe open at both the ends in fundamental mode.

A tube open at both ends has length 47 em. Calculate the fundamental frequency of air column. (Neglect end correction. Speed of sound in air is 3.3 x 10²m/s}

Draw neat labelled diagrams for modes of vibration of an air column in a pipe when it is closed at one end.

Hence derive an expression for fundamental frequency in each case.

Define coefficient of mutual induction. 

Explain the phenomenon of mutual induction.

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.

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.

State the Stefan-Boltzmann law.

A pair of adjacent coils has a mutual inductance of 1.5 H. If the current in one coil changes from 0 to 10 A in 0.2 s, what is the change of flux linkage with the other coil?

An emf of 96.0 mV is induced in the windings of a coil when the current in a nearby coil is increasing at the rate of 1.20 A/s. What is the mutual inductance (M) of the two coils?