Moving Charges and Magnetism — Physics STD 12 Science — Question

Three capacitances of capacity 10 μF, 5 μF  and 5 μF  are connected in parallel. The total capacity will be

(a) 10 μF

(b) 5 μF

(c) 20 μF

(d) None of the above

An e.m.f. of 5 volt is produced by a self inductance, when the current changes at a steady rate from 3 A to 2 A in 1 millisecond. The value of self inductance is

(a) Zero

(b) 5 H

(c) 5000 H

(d) 5 mH

A proton enters a magnetic field of flux density 1.5   with a velocity of  2   at an angle of 30°  with the field. The force on the proton will be

(a) 2.4

(b) 0.24

(c) 24

(d) 0.024

There is an electric field E in X-direction. If the work done on moving a charge 0.2 C through a distance of 2 m  along a line making an angle 60°  with the X-axis is 4.0, what is the value of E

(a) N/C

(b) 4 N/C

(c) 5 N/C

(d) None of these

Electric lines of force about a negative point charge are:

A charged particle is whirled in a horizontal circle on a frictionless table by attaching it to a string fixed at one point. If a magnetic field is switched on in the vertical direction the tension in the string.

1. Will increase.
2. Will decrease.
3. Will remain the same.
4. May increase or decrease.

The value of scattering angle of alpha particle for maximum value of impact parameter is :

Monochromatic green light of wavelength 5  illuminates a pair of slits 1 mm apart. The separation of bright lines on the interference pattern formed on a screen 2 m away is

(a) 0.25 mm

(b) 0.1 mm

(c) 1.0 mm

(d) 0.01 mm

A 60 watt bulb operates on 220V supply. The current flowing through the bulb is

(a) 11/3 amp

(b) 3/11 amp

(c) 3 amp

(d) 6 amp

The current is flowing in south direction along a power line. The direction of magnetic field above the power line (neglecting earth's field) is

(a) South

(b) East

(c) North

(d) West