Current Electricity — Physics STD 12 Science — Question

Two identical magnetic dipoles of magnetic moments 1.0 A-m² each, placed at a separation of 2m with their axis perpendicular to each other. The resultant magnetic field at a point midway between the dipoles is

(a) 5

(b)

(c)

(d) None of these

For a single charge the field lines start or ends at:

Energy released in the fission of a single   nucleus is 200 MeV. The fission rate of a  fuelled reactor operating at a power level of 5W is

(a) 1.56

(b) 1.56

(c) 1.56

(d) 1.56

An electric charge in uniform motion produces:

A rod AB moves with a uniform velocity v in a uniform magnetic field as shown in figure.

1. The rod becomes electrically charged.
2. The end A becomes positively charged.
3. The end B becomes positively charged.
4. The rod becomes hot because of Joule heating.

Sensitivity of potentiometer can be increased by:

Reciprocal of Impedance is:

When   transforms to , then the number of the emitted a- and b-particles is, respectively

(a) 8α, 7β

(b) 4α, 7β

(c) 4 α, 4β

(d) 4α, 1β

What is the effective capacitance between points X and  Y

(a) 24 μF

(b) 18 μF

(c) 12 μF

(d) 6 μF

Resistors of 1, 2, 3 ohm are connected in the form of a triangle. If a 1.5 volt cell of negligible internal resistance is connected across 3 ohm resistor, the current flowing through this resistance will be

(a) 0.25 amp

(b) 0.5 amp

(c) 1.0 amp

(d) 1.5 amp