Current Electricity — Physics STD 12 Science — Question

An observer on earth observes that wave length of spectral line in spectrum of a milky way shifts towards red end of spectrum. According to the observer, the milky-way is:

Pure inductance of 3.0 H is connected as shown below. The equivalent inductance of the circuit is

(a) 1 H

(b) 2 H

(c) 3 H

(d) 9 H

The first excited state of hydrogen atom is 10.2 eV above its ground state. The temperature is needed to excite hydrogen atoms to first excited level, is

(a) 7.9

(b) 3.5

(c) 5.8

(d) 14

Which conservation law is obeyed in Einstein's photoelectric equation?

A magnet NS is suspended from a spring and while it oscillates, the magnet moves in and out of the coil C. The coil is connected to a galvanometer G. Then as the magnet oscillates,

(a) G shows deflection to the left and right with constant amplitude

(b) G shows deflection on one side

(c) G shows no deflection.

(d) G shows deflection to the left and right but the amplitude steadily decreases.

In an ideal parallel LC circuit, the capacitor is charged by connecting it to a D.C. source which is then disconnected. The current in the circuit.

The coefficient of mutual induction between two coils is 4H. If the current in the primary reduces from 5A to zero in 10^-3 second then the induced emf in the secondary coil will be

Hydrogen atom excites energy level from fundamental state to n = 3. Number of spectral lines according to Bohr, is?

Five lumen/watt is the luminous efficiency of a lamp and its luminous intensity is 35 candela. The power of the lamp is

(a) 80 W

(b) 176 W

(c) 88 W

(d) 36 W

Which one of the following planet has the longest day

(a) Venus

(b) Mars

(c) Mercury

(d) Earth