Physics Test 29...

In a capillary tube of radius 'R', a straight thin metal wire of radius 'r' (R > r) is inserted symmetrically and one end of the combination is dipped vertically in water such that the lower end of the combination is at same level. The rise of water in the capillary tube is [T = surface tension of water, ρ = density of water, g = gravitational acceleration]

Three magnetic materials are listed below

(A) paramagnetics

(B) diamagnetics

(C) ferromagnetics

Choose the correct order of the materials in increasingorder of magnetic susceptibility.

Two wires A and B are of the same materials. Their lengths are in the ratio 1 : 2 and the diameters are in the ratio 2 : 1, When stretched by force F_A and F_B respectively they get equal increase in their lengths. Then the ratio  should be:

A wire of length ‘l’ and resistance 100 Ω is divided into 10 equal parts. The first 5 parts are connected in series while the next 5 parts are connected in parallel. The two combinations are again connected in series. The resistance of this final combination is:

Two small spherical metal balls, having equal masses, are made from materials of densities ρ₁ and ρ₂ (ρ₁ = 8ρ₂) and have radii of 1 mm and 2 mm, respectively, They are made to fall vertically (from rest) in a viscous medium whose coefficient of viscosity equals η and whose density is 0.1 ρ₂. The ratio of their terminal velocities would be,

An ac source is connected to a capacitor C. Due to decrease in its operating frequency:

Light travels a distance x in time t₁ in air and 10x in time t₂ in another denser medium. What is the critical angle for this medium?

Electrons used in an electron microscope are accelerated by a voltage of 25 kV. If the voltage is increased to 100 kV then the de-Broglie wavelength associated with the electrons would

The two ends of a long cylinder containing gas are maintained at different temperatures. Which of the following quantities will have the same value throughout the cylinder?

Addition of trivalent impurity to a pure semiconductor creates many