Ray Optics and Optical Instruments — Physics STD 12 Science — Question

The colour of bright fringes nearest to the central achromatic fringe in the interference pattern with white light will be:

Which of the following particles will experience maximum magnetic force circle when projected with the same velocity perpendicular to a magnetic field?

A ray is reflected in turn by three plain mirrors mutually at right angles to each other. The angle between the incident and the reflected rays is (a) 90°(b) 60°(c) 180°   (d) None of these

What is the order of potential difference built up by the Van de Graff generator?

A moving charge produces :

Out of the following, waves of which frequency can penetrate ionosphere?

Assertion : The ionising power of b-particle is less compared to a-particles but their penetrating power is more.
Reason     : The mass of b-particle is less than the mass of a-particle.(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.(c) If assertion is true but reason is false.(d) If the assertion and reason both are false.

When an ideal battery is joined with an external resistance in an electric circuit, a current i flows. through it. If another battery like this battery is joined in parallel with this battery, then the magnitude of current flowing in the battery will become:

If in a plano-convex lens, the radius of curvature of the convex surface is 10 cm and the focal length of the lens is 30 cm, then the refractive index of the material of lens will be(a) 1.5(b) 1.66(c) 1.33(d) 3