Atoms — Physics STD 12 Science — Question

The current i in an induction coil varies with time t according to the graph shown

in figure. Which of the following graphs shows the induced emf (e) in the coil with time

(a)

(b)

(c)

(d)

A body has – 80 micro coulomb of charge. Number of additional electrons in it will be

(a) 8

(b) 80

(c) 5

(d) 1.28

Joining of light nuclei of elements to form a heavy nucleus with the release of energy is called:

Two sources give interference pattern which is observed on a screen, D distance apart from the sources. The fringe width is 2w. If the distance D is now doubled, the fringe width will

(a) Become w/2

(b) Remain the same

(c) Become w

(d) Become 4w

In a circuit with a coil of resistance 2 ohms, the magnetic flux changes from 2.0 Wb to 10.0 Wb in 0.2 second. The charge that flows in the coil during this time is

(a) 5.0 coulomb

(b) 4.0 coulomb

(c) 1.0 coulomb

(d) 0.8 coulomb

Two conducting circular loops F and G are kept in a plane on either side of a straight current-carrying wire as shown in the figure below. If the current in the wire decreases in magnitude, the induced current in the loops will be.

Electric lines of force about a negative point charge are:

A dip circle is taken to geomagnetic equator. The needle is allowed to move in a vertical plane perpendicular to the magnetic meridian. The needle will stay:

Two heater wires of equal length are first connected in series and then in parallel. The ratio of heat produced in the two cases is

(a) 2 : 1

(b) 1 : 2

(c) 4 : 1

(d) 1 : 4

Figure gives a system of logic gates. From the study of truth table it can be found that to produce a high output (1) at R, we must have

(a) X = 0, Y = 1

(b) X = 1, Y = 1

(c) X = 1, Y = 0

(d) X = 0, Y = 0