Semiconductor Electronic: Material, Devices And Simple Circuits — Physics STD 12 Science — Question

Three charges each of magnitude q are placed at the corners of an equilateral triangle, the electrostatic force on the charge placed at the center is (each side of triangle is L)

(a) Zero

(b)

(c)

(d)

Which of the following quantities increase when wavelength is increased? Consider only the magnitudes.

1. The power of a converging lens.
2. The focal length of a converging lens.
3. The power of a diverging lens.
4. The focal length of a diverging lens.

Three long, straight and parallel wires carrying currents are arranged as shown in figure. The force experienced by 10 cm length of wire Q is

(a) 1.4  towards the right	(b) 1.4  towards the left
(c) 2.6  to the right	(d) 2.6  to the left

The pole strength of a bar magnet is 48 ampere-metre and the distance between its poles is 25 cm. The moment of the couple by which it can be placed at an angle of 30^o with the uniform magnetic intensity of flux density 0.15 Newton /ampere-metre will be

(a) 12 Newton × metre	(b) 18 Newton × metre
(c) 0.9 Newton × metre	(d) None of the above

Coulomb's law is a confirmation of______

Which theory explained that electrons revolved in circular orbits?

A straight copper wire is moved in a uniform magnetic field such that it cuts the magnetic lines of force. Then

If in the experiment of Wheatstone's bridge, the positions of cells and galvanometer are interchanged, then balance points will

(a) Change

(b) Remain unchanged

(c) Depend on the internal resistance of cell and resistance of galvanometer

(d) None of these

Equal charges are located at three corners of an equilateral triangle. The true statement for electric potential V and electric field intensity E at the centre O of the triangle will be: