Electric Charges and Fields — Physics STD 12 Science — Question

Two statements are given-one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below. Assertion (A): Magnetic field is useful in producing parallel beam of charged particle. Reason (R): Magnetic field inhibits the motion of charged particle moving across it.

The length of a wire of a potentiometer is 100 cm, and the emf of its standard cell is E volt.  It is employed to measure the e.m.f of a battery whose internal resistance is 0.5 W.  If the balance point is obtained at l = 30 cm from the positive end, the e.m.f. of the battery is (where i is the current in the potentiometer)

(a)

(b)

(c)

(d)

A 10 metre wire kept in east-west falling with velocity 5 m/sec perpendicular to the field 0.3 .  The induced e.m.f. across the terminal will be

(a)  0.15 V

(b) 1.5 mV

(c)  1.5 V

(d) 15.0 V

A pure resistor is joined with a capacitor. The magni- tude of tangent of their phase difference in the cir- cuit is:

In Young's double slit experiment, the intensity on the screen at a point where path difference is l is K. What will be the intensity at the point where path difference is λ/4

(a)

(b)

(c) K

(d) Zero

Wavelength of an electron having energy 10 keV is ....................A⁰:

In which of the following transitions will the wavelength be minimum?

In a region, the potential is represented by V(x, y, z) = 6x - 8xy - 8y + 6yz, where V is in volts and x, y, z are in metres. The electric force experienced by a charge of 2 coulomb situated at point (1, 1, 1) is:

An ice cube is suspended in vacuum in a gravity free hall. As the ice melts it.

1. Will retain its cubical shape.
2. Will change its shape to spherical.
3. Will fall down on the floor of the hall.
4. Will fly up.

On the bombardment of neutron with Boron. a-particle is emitted and product nuclei formed is

(a)

(b)

(c)

(d)