Physics Past Questions and Answers

Which of the following conditions are necessary and sufficient for total internal reflection to take place at the boundary between two optical media? i. light is passing from optically denser medium to optically less dense medium. ii. light is passing from optically less dense medium to optically denser medium. iii. angle of incidence is greater. iv. angle of incidence is lesser

A I and ii only
B Ii and iii only
C Ii and iv only
D I and iii only
E Ii and iv only

Question 252:

A man of mass 50kg ascends a flight of stairs 5m high in 5 seconds. If acceleration due to gravity is 10ms-2, the power expended is

A 100W
B 200W
C 250W
D 400W
E 500W

Question 253:

Which of the following arrangements in the sequence shown can be used to obtain a pure spectrum of white light?

A Source, slit, converging lens, prism, converging lens, screen.
B Source, slit, diverging lens, prism, diverging lens, screen.
C Source, converging lens, prism, diverging lens, screen.
D Source, slit, prism, diverging lens, converging lens, screen.
E Source, slit, prism, diverging lens, sreen.

Question 254:

A milliameter with full scale deflection of 10mA has an internal resistance of 5 ohms. It would be converted to an ammeter with a full scale deflection of 1A by connecting a resistance of

A \(\frac{5}{99}\)ohms in series with it
B \(\frac{5}{99}\)ohms in parallel with it
C \(\frac{99}{5}\)ohms in series with it
D \(\frac{99}{5}\)ohms in parallel with it
E 2 ohms in series with it

Question 255:

The linear expansivity of brass is 2 x 10-5oC-1. If the volume of a piece of brass is 10cm3 at 0oC, what will be its volume at 100oC?

A 10.02cm3
B 10.04cm3
C 10.06cm3
D 10.20cm3
E 102.00cm3