A box of mass 8 kg slides at a speed of across a smooth level floor before it encounters a rough patch of length 3.0 m. The frictional force on the box due to this part of the floor is 70 N. What is the speed of the box when it leaves this rough surface? What length of the rough surface would bring the box completely to rest?
A ball of mass 0.5 kg collides with a wall at a speed of
and bounces back with a speed of
.If the average force exerted by the ball is 1100 N calculate the impulse and the time for which the collision lasted.
A mass of 10 kg, is released from rest on an incline that makes a 30° angle with the horizontal. In 2 s, the mass is observed to have moved a distance of 4 m. What is the coefficient of kinetic friction between the mass and the surface of the incline? Draw the free body diagram.
See Answer →b) for
Obtain the derivative and unit tangent vector at for a vector function
Determine the projection of on
where
and
The refractive indices of core (n1) and cladding (n2) materials of two optical fibres A and B are as follows: and
and and
Which of the two fibres will have higher gathering capacity?
See Answer →A laser cavity of 25 cm length sustains the radiation of 6300 Å. Calculate the number of modes and mode separation. If the spread in wavelength is 0.02 Å, calculate the coherence length and coherence time.
See Answer →Describe the types of optical fibres. How can the pulse dispersion in the optical fibre be reduces?
See Answer →Explain the role of resonant cavity in determining the coherence and monochromaticity of a laser light.
See Answer →Explain the three light-matter interactions with the help of atomic level diagrams. Write the corresponding Einstein’s equations.
See Answer →A plane light wave of wavelength 580 nm falls on a long narrow slit of width 0.5 mm. (i) Calculate the angles of diffraction for the first two minima. (ii) How are these angles influenced if the width of slit is changed to 0.2 mm? (iii) If a convex lens of focal length 0.15 m is now placed after the slit, calculate the separation between the second minima on either side of the central maximum.
See Answer →Obtain an expression for intensity distribution in a single slit diffraction pattern.
See Answer →In the experimental set up to observe diffraction pattern of a straight edge, the distance of the edge from the source is 30 cm and the distance of the screen from the edge is 40 cm. The wavelength of the light used is 480 x 10–5 cm. Calculate the position of the first and third minima from the edge of the geometrical shadow.
See Answer →Interference fringes are formed by reflection from a thin air wedge by using sodium light of wavelength of 5893 Å When viewed perpendicularly, 12 fringes are observed in a distance of 1cm. Calculate the angle of wedge.
See Answer →Obtain an expression of the displacement of the nth bright fringe in double slit experiment when a thin transparent plate of thickness t and refractive index is introduced in the path of one of the two interfering waves. How the fringe-width is affected with the introduction of the plate?
See Answer →A Michelson interferometer is illuminated with monochromatic light. When one of the mirrors is moved fringes cross the field of view. Determine the wavelength of the incident light.
In a Young’s double slit experiment, a monochromatic light of wavelength 600nm is used. The slits are 0.2mm apart. An interference pattern is observed on a screen 0.6 m away. Calculate the distance between the central maxima and the third minima on the screen.
See Answer →Explain how Michelson interferometer can be used to determine the wavelength of light?
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