Moving Charges and Magnetism — Physics STD 12 Science — Question

12 cells each having same emf are connected in series with some cells wrongly connected. The arrangement is connected in series with an ammeter and two cells which are in series. Current is 3 A when cells and battery aid each other and is 2 A when cells and battery oppose each other. The number of cells wrongly connected is

(a) 4

(b) 1

(c) 3

(d) 2

A charge of   is placed on each of the 64 identical drops of radius 2cm. They are then combined to form a bigger drop. Find its potential             

(a) 7.2

(b) 7.2

(c) 1.44

(d) 1.44

Which of the following is correct for resistance of a material ?

Which of the following is diamagnetism

(a) Aluminium

(b) Quartz

(c) Nickel

(d) Bismuth

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:

The absorption transitions between the first and the fourth energy states of hydrogen atom are 3. The emission transitions between these states will be    

(a) 3

(b) 4

(c) 5

(d) 6

The formation of depletion region in a p-n junction diode is due to

The field due to a magnet at a distance R from the centre of the magnet is proportional to

(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

Unit of pole strength is :