Physics Test - ...

In an experiment to determine the velocity of sound in air at room temperature using a resonance tube, the first resonance is observed when the air column has a length of \(20.0 \mathrm{~cm}\) for a tuning fork of frequency \(400 \mathrm{~Hz}\) is used. The velocity of the sound at room temperature is \(336 \mathrm{~ms}^{-1}\). The third resonance is observed when the air column has a length of _________ \(\mathrm{cm}\).

Unit of magnetic flux is:

The angular momentum of a particle performing uniform circular motion is L. If the kinetic energy of the particle is doubled and frequency is halved, then angular momentum becomes:

A man increases his speed by 2m/s, then his kinetic energy gets doubled. The original speed of the man is:

In whose model an atom is a spherical cloud of positive charges with electrons embedded in it?

What is the direction of force of friction acting on a body moving on a fixed surface?

A closely wound solenoid of \(2000\) turns and area of cross-section \(1.6 \times 10^{-4} m^{2},\) carrying a current of \(4.0 A,\) is suspended through its center allowing it to turn in a horizontal plane.

(a) What is the magnetic moment associated with the solenoid?

(b) What is the force and torque on the solenoid if a uniform horizontal magnetic field of \(7.5 \times 10^{-2} {~T}\) is set up atan angle of \(30^{\circ}\) with the axis of the solenoid?

The \(\mathrm{V}_{\text{rms }}\) of gas molecules is \(300 \mathrm{~m}/\mathrm{sec}\). If it's absolute temperature is reduced to half and molecular weight is doubled the \(\mathrm{V}_{\mathrm{rms}}\) will become?

A body cools from \(80^{\circ} \mathrm{C}\) to \(60^{\circ}\) in 5 minutes. The temperature for the surrounding is \(20^{\circ} \mathrm{C}\). The time it takes to cool from \(60^{\circ} \mathrm{C}\) to \(40^{\circ} \mathrm{C}\) is :