Electromagnetic Induction — Physics STD 12 Science — Question

Ultraviolet spectrum can be studied by using a:

Three charges are placed at the vertices of an equilateral triangle of side ‘a’ as shown in the following figure. The force experienced by the charge placed at the vertex A in a direction normal to BC is

(a)

(b)

(c) Zero

(d)

Two circular loops of equal radii are placed coaxially at some separation. The first is cut and a battery is inserted in between to drive a current in it. The current c~anges slightly because of the variation in resistance with temperature. During this period, the two loops:

1. Attract each other.
2. Repel each other.
3. Do not exert any force on each other.
4. Attract or repel each other depending on the sense of the current.

The optical fibre works on the principle of :

Two coherent sources of different intensities send waves which interfere. The ratio of maximum intensity to the minimum intensity is 25. The intensities of the sources are in the ratio

(a) 25 : 1

(b) 5 : 1

(c) 9 : 4

(d) 25 : 16

The magnetic dipole moment of a current loop is independent of:

The carrier frequency generated by a tank circuit containing 1 nF capacitor and 10 mH inductor is

(a) 1592 Hz

(b) 1592 MHz

(c) 1592 kHz

(d) 159.2 Hz

A element used for radioactive carbon dating for more than 5600 years is

(a) C - 14

(b) U - 234

(c) U - 238

(d) Po - 94

 denotes the mass of a proton and  that of a neutron. A given nucleus, of binding energy B, contains Z protons and N neutrons. The mass M(N, Z) of the nucleus is given by (c is the velocity of light)

(a)	(b)
(c)	(d)

Which decay increases the atomic number?