14. If a document is to be produced using a duplicating
camera, where should the document be placed in order to obtain an exact copy?
A. At the point which is twice the focal length of the
camera
B. At the optical centre of the lens of the camera
C. Between the
principal focus and a point twice the
focal length of the lens of the camera
D. Beyond a
point twice the focal length of the lens
Answer
15. If the speed of light in water is 2.26 X 108m/s
and the speed of light in air is 3 X 108m/s, calculate the refractive
index of water.
A. 1.33
B. 1.23
C. 1.45
D.1.56
Answer
16. What is the energy with which an incident light of
wavelength 10-7m falls on a metal and electrons are emitted? [c=3X108m/s, h= 6.63 X10-34Js ]
A. 1.99X10-18J
B. 1.99X10-16J
C. 1.99X10-19J
D.
1.99X10-20J
Answer
Answer
18. X-rays can be used in the study of crystal
structures because they
A. have long
reaching wavelength
B. have an extremely short wavelength
C. are very fast
D. are invisible
Answer
19. Which of the following is both transverse and
mechanical?
A. sound waves
B. radio waves
C. water waves
D.
X-rays
Answer
20. When primary and secondary colours are combined to
produce white light, the phenomenon is known as
A.Complementary colours mixing
B. Subtractive
colours mixing
C. Secondary and
primary colours mixing
D. Primary
colours mixture
Answer
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