Physics Test - ...

A copper sphere of mass \(2 \) g contains nearly \(2 \times 10^{22}\) atoms. The charge on the nucleus of each atom is \(29 \) e. What fraction of the electrons must be removed from the sphere to give it a charge of \(+2 \mu C\) ?

The mass of spaceship is 1000 kg. It is to be launched from the earth’s surface out into free space. The value of ‘g’ and ‘R’ (radius of earth) are 10 m/s² and 6400 km respectively. The required energy for this work will be:

Infrared radiation was discovered in 1800 by ______

A \(4.5 ~cm\) long needle is placed \(12~ cm\) away from a convex mirror of focal length \(15~ cm\). Give the location of the image and the magnification.

A standing wave is formed by the superposition of two waves travelling in opposite directions. The transverse displacement is given by \(y(x, t)=0.5 \sin \left(\frac{5 \pi}{4} x\right) \cos (200 \pi t)\). What is the speed of the travelling wave moving in the positive \(x\) direction? \((x\) and \(t\) are in meter and second, respectively).

_____________ factor that affects the heat of reaction which is based on Kirchoff’s equation.

An excited hydrogen atom emits a photon of wavelength \(\lambda\) in returning to the ground state. If \(R\) is the Rydberg constant, then the quantum number \(n\) of the excited state will be:

Two coils of self-inductance \(L_1\) and \(L_2\) are placed closer to each other so that total flux in one coil is completely linked with others. If M is mutual inductance between them, then: