Physics Past Questions and Answers

An object is placed 15cm in front of a concave mirror of focal length 20cm. The image formed is ____________

A Real, inverted and diminished
B Real, inverted and magnified
C Virtual, erect and diminished
D Virtual, erect and magnified
E Virtual, inverted and magnified

Question 87:

Given the same amount of beat, a quantity of water will reach a higher temperature in a brass pot than in a clay pot of the same mass because

A Brass is less dense than clay
B Clay expands more slowly than brass
C Clay loses heat faster than brass
D The specific heat capacity of brass is higher than that of clay
E The specific heat capacity of brass is lower than of clay.

Question 88:

When an astronomical telescope is in normal adjustment, the focal length of the objective lens is 50cm and that of the eye piece is 5.0cm. What is the distance between the lenses?

A 10.0cm
B 30.0cm
C 45.0cm
D 55.0cm
E 250.0cm

Question 89:

The main function of the commutator in a simple d.c. motor is to ____________

A Enable the armature to rotate freely
B Increase the flux linking the armature windings
C Maintain a direct current in the armature
D Provide uniform magnetic field around the armature
E Reverse the direction of the current in the armature.

Question 90:

An object 3.00m high is placed at a distance of 7.50m from a pin-hole camera. If the image height is 6.00 cm, what is the distance of the film from the pin-hole?

A 3.75cm
B 7.50cm
C 15.00cm
D 30.00cm
E 150.00 cm