Atomic and Nuclear Physics — Physics STD 12 Science — Question

If in nature there may not be an element for which the principal quantum number n > 4, then the total possible number of elements will be(a) 60(b) 32(c) 4(d) 64

Magnetic field intensity is defined as:

Television signals broadcast from the moon can be received on the earth while the TV broadcast from Delhi cannot be received at places about 100 km distant from Delhi. This is because(a) There is no atmosphere around the moon(b) Of strong gravity effect on TV signals(c) TV signals travel straight and cannot follow the curvature of the earth(d) There is atmosphere around the earth

In intrinsic semiconductors:

Magnitude of potential difference across L. C and R in a series LCR circuit is 100 V. If resistor is re- moved, then magnitude of current in the circuit is:

When a ferromagnetic material goes through a hysteresis loop, the magnetic susceptibility:

Two magnets of same size and mass make respectively 10 and 15 oscillations per minute at certain place. The ratio of their magnetic moments is(a) 4 : 9(b) 9 : 4(c) 2 : 3    (d) 3 : 2

A nuclear reaction with positive Q value is:

Wires P and Q have the same resistance at ordinary (room) temperature. When heated, resistance of P  increases and that of Q decreases. We conclude that(a) P and Q are conductors of different materials(b) P is N-type semiconductor and Q is P-type semiconductor(c) P is semiconductor and Q is conductor(d) P is conductor and Q is semiconductor

An electric bulb marked 40 W and 200 V, is used in a circuit of supply voltage 100 V. Now its power is(a) 100W(b) 40W(c) 20W   (d) 10W