Use of the mirror formula - Jamb Physics Past Questions and Answers

Question 11:

• JAMB 1991

Which of the following correctly, describes the image of an object, 4cm from a diverging lens of focal length 12cm?

A. The image is virtual, 3cm in front of the lens
B. The image is real, 6cm behind the lens
C. The image is virtual, 6cm in front of the lens
D. The image is real, 3cm in front the lens

Question 12:

• JAMB 1992

A concave mirror has a radius of curvature of 36cm. At what distance from the mirror should an object be placed to give a real image three times the size of the object?

A. 12cm
B. 24cm
C. 48cm
D. 108cm

Question 13:

• JAMB 1993

If the focal length of a camera lens is 20cm, the distance from the film at which the lens must be set to produce a sharp image of an object 100cm away is

A. 17cm
B. 20cm
C. 25cm
D. 100cm

Question 14:

• JAMB 1994

An object is placed in front of a converging lens of a focal length 20cm. The image is virtual and has a magnification of 2. What is the distance of the object from the lens?

A. 5cm
B. 10cm
C. 30cm
D. 40cm