Current Electricity — Physics STD 12 Science — Question

The wavelength of light visible to eye is of the order of

(a)

(b)  m

(c) 1 m

(d) 6  m

At a certain place the horizontal component of the earth’s magnetic field is B₀ and the angle of dip is 45^o. The total intensity of the field at that place will be

(a) B0

(b)

(c) 2B0

(d)

An electric dipole is kept in non-uniform electric field. It experiences

(a) A force and a torque	(b) A force but not a torque
(c) A torque but not a force	(d) Neither a force nor a torque

Magnetic effect of current was discovered by

(a) Faraday

(b) Oersted

(c) Ampere

(d) Bohr

If a capacitor is connected to two different A.C. generators, then the value of capacitive reactance is:

Indicate which one of the following system is digital

(a) Pulse position modulation	(b) Pulse code modulation
(c) Pulse width modulation	(d) Pulse amplitude modulation

Two rods of same material and length have their electric resistance in ratio 1 : 2. When both rods are dipped in water, the correct statement will be

(a) A has more loss of weight	(b) B has more loss of weight
(c) Both have same loss of weight	(d) Loss of weight will be in the ratio 1 : 2

A 36 W galvanometer is shunted by resistance of 4W. The percentage of the total current, which passes through the galvanometer is

(a) 8 %

(b) 9 %

(c) 10 %

(d) 91 %

Which one of the following is more monocromatic?

The heat generated through 2 ohm and 8 ohm resistances separately, when a condenser of 200 μF capacity charged to 200 V is discharged one by one, will be

(a) 4 J and 16 J respectively	(b) 16 J and 4 J respectively
(c) 4 J and 8 J respectively	(d) 4 J and 4 J respectively