Physics

Water has been filled in a vertical capillary tube upto the top after closing its lower end by a finger Consider radius of capillary r = 1 mm, surface tension is 70 dyne/cm and g = 980 cm/sec2. Which of the option is correct when finger is removed?

If the gravitational acceleration at the surface of earth is g, then increase in potential energy in lifting an object of mass m from earth surface to a height equal to half of radius of earth from surface will be:

The length of a potentiometer wire is ?. A cell of emf E is balanced at a length ?/4 from the positive end of the wire. If the length of the wire is increased by ?/2, at what distance will the same cell give a balanced point? (Potentiometer battery is ideal)

A vernier caliper has 10 main scale divisions coinciding with 11 vernier scale divisions. 1 main scale division equals 5 mm. The least count of the device is

The spectrum of a black body at two temperature 127°C and 527°C is shown in the figure. Let A1 and A2 be the areas under the two curves respectively. The value A_1/A_{2 is:}

The dimensions of angular impulse is equal to

If a star emitting light of wavelength 500 nm is moving towards earth with a velocity of 1.5 ´ 106 m/s then the shift in the wavelength due to doppler's effect will be:

Which of the following graph represents the damped oscillation motion?

When a metallic surface is illuminated with radiation of wavelength l, the stopping potential is V. If the same surface is illuminated with radiation of wavelength 2l, the stopping potential is  V . The threshold wavelength metallic surface is

The core of a transformer is laminated to reduce energy losses due to