Magnetism and Matter — Physics STD 12 Science — Question

Ammeter and milli-ammeter both are made from galvanometer. Which of them has greater resistance?

From what electric dipole of electric field is found and for which two cases is the result simple?

A boy is standing on a platform which is free to rotate about its axis. The boy holds an open umbrella in his hand. The axis of the umbrella coincides with that of the platform. The moment of inertia of ''the platform plus the boy system'' is 3.0 × 10^-3kg-m² and that of the umbrella is 2.0 × 10³kg-m². The boy starts spinning the umbrella about the axis at an angular speed of 2.0rev/s with respect to himself. Find the angular velocity imparted to the platform.

In a photoelectric effect, the yellow light is just able to emit electrons, will green light emit photoelectrons? What about red light?

A steel rod of length 1m rests on a smooth horizontal base. If it is heated from 0^°C to 100^°C, what is the longitudinal strain developed?

Give characteristics of electric field lines.

The electric force experienced by a charge of 1.0 × 10^-6C is 1.5 × 10^-3N. Find the magnitude of the electric field at the position of the charge.

A parallel beam of light of 500 nm falls on a narrow slit and the resulting diffraction pattern is observed on a screen 1 m away. It is observed that the first minimum is at a distance of 2.5 mm from the centre of the screen. Calculate the width of the slit.

The electric field intensity and electric potential at a point due to a point charge are 30 Newton/ Coulomb and 15 Joule/Coulomb respectively. Find (i) the distance of the charge from the observation point and (ii) the magnitude of the charge.

Explain the proof of validity of Einstein's equation of photoelectric effect.