Atoms — Physics STD 12 Science — Question

The ultimate individual unit of magnetism in any magnet is called

(a) North pole

(b) South pole

(c) Dipole

(d) Quadrupole

A glass lens is placed in a medium in which it is found to behave like a glass plate. Refractive index of the medium will be

(a) Greater than the refractive index of glass

(b) Smaller than the refractive index of glass

(c) Equal to refractive index of glass

(d) No case will be possible from above

Two sources give interference pattern which is observed on a screen, D distance apart from the sources. The fringe width is 2w. If the distance D is now doubled, the fringe width will

(a) Become w/2

(b) Remain the same

(c) Become w

(d) Become 4w

There exists an electric field of 1N/C along Y direction. The flux passing through the square of 1m placed in XY plane inside the electric field is?

Radius of  nucleus is 3 Fermi. The radius of  nucleus will be

(a) 5 Fermi

(b) 6 Fermi

(c) 11.16 Fermi

(d) 8 Fermi

125 identical drops each charged to the same potential of 50 volts are combined to form a single drop. The potential of the new drop will be

(a) 50 V

(b) 250 V

(c) 500 V

(d) 1250 V

The ratio of longest wavelength and the shortest wavelength observed in the five spectral series of emission spectrum of hydrogen is

(a)

(b)

(c) 25

(d)

A temporary magnet is made of:

Two non-ideal batteries are connected in parallel. Consider the following statements:

1. The equivalent emf is smaller than either of the two emfs.
2. The equivalent internal resistance is smaller than either of the two internal resistances.

1. Both A and B are correct.
2. A is correct but B is wrong.
3. B is correct but A is wrong.
4. Both A and B are wrong.

A lens (focal length 50 cm) forms the image of a distant object which subtends an angle of 1 milliradian at the lens. What is the size of the image

(a) 5 mm

(b) 1 mm

(c) 0.5 mm

(d) 0.1 mm