31. The process whereby a liquid turns spontaneously into vapour is called
- A. regelation
- B. evaporation
- C. boiling
- D. sublimation
Correct Option: Answer is B
The process in which liquid change into vapour without boiling is called evaporation.
32. The differences observed in solids, liquids and gases may be accounted for by
- A. their relative masses
- B. their melting points
- C. the spacing and forces acting between the molecules
- D. the different molecules in each of them
Correct Option: Answer is C
33. Convex mirrors are used as driving mirrors because images formed are
- A. erect, Virtual and diminished
- B. erect, real and diminished
- C. erect, virtual and magnified
- D. inverted, virtual and diminished
Correct Option: Answer is A
34. Musical instruments playing the same note can be distinguished from one another owing to the difference in their
- A. quality
- B. pitch
- C. intensity
- D. loudness
Correct Option: Answer is B
35.
In the diagram shown, If the south-poles of two magnets stroke a steel bar, the polarities at T and V will respectively be
- A. north and south
- B. south and south
- C. north and north
- D. south and north
Correct Option: Answer is C
36. In homes, electrical appliances and lamps are connected in parallel because
- A. less current will be used
- B. less voltage will be used
- C. parallel connection does not heat up the wires
- D. series connection uses high voltage
Correct Option: Answer is D
37. An object moves in a circular path of radius 0.5m with a speed of 1ms\(^{-1}\). What is its angular velocity?
- A. 8rads\(^{-1}\)
- B. 4rads\(^{-1}\)
- C. 1rads\(^{-1}\)
- D. 2rads\(^{-1}\)
Correct Option: Answer is D
Angular velocity
V=rw
Where V=1m/s
r=0.5m
w=?
V=rw
1=0.5×w
W=1/0.5
W=2rad/s
38. What effort will a machine of efficiency 90% apply to a load of 180N if its efforts arm is twice as long as its load arm?
- A. 100N
- B. 90N
- C. 80N
- D. 120N
Correct Option: Answer is A
39.
Calculate the effective capacitance of the circuit in the diagram given
- A. 4μf
- B. 3μf
- C. 2μf
- D. 1μf
Correct Option: Answer is D
40.Which of the following diagrams represents correctly an n-p-n transistor?
i.
ii.
iii.
- A. i
- B. ii
- C. iii