Alternating Current — Physics STD 12 Science — Question

To increase both the resolving power and magnifying power of a telescope:

When a ray of light passes from a denser to a rarer medium, some part of it gets ....... into the denser medium:

A conducting loop is placed in a uniform magnetic field with its plane perpendicular to the field. An emf is induced in the loop if:

Assertion  :   Electric lines of force cross each other.
Reason      : Electric field at a point superimpose to give one resultant electric field.(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 assertion is false but reason is true.

The waves which are electromagnetic in nature are:

In a certain double slit experimental arrangement interference fringes of width 1.0 mm each are observed when light of wavelength 5000 Å is used. Keeping the set up unaltered, if the source is replaced by another source of wavelength 6000 Å, the fringe width will be(a) 0.5 mm(b) 1.0 mm(c) 1.2 mm(d) 1.5 mm

A person wears glasses of power – 2.5 D. The defect of the eye and the far point of the person without the glasses are respectively(a) Farsightedness, 40 cm(b) Nearsightedness, 40 cm(c) Astigmatism, 40 cm(d) Nearsightedness, 250 cm