31. The temperature gradient across a copper rod of thickness 0.02m, maintained at two temperature junctions of 20º and 80ºC respectively is?
- A. 3.0 x 102km−1
- B. 3.0 x 103km−1
- C. 5.0 x 103km−1
- D. 3.0 x 104km−1
32. Calculate the mass of ice that would melt when 2kg of copper is quickly transferred from boiling water to a block of ice without heat loss (specific heat capacity of copper = 400Jkg1k−1, latent heat of fusion of ice = 3.3 x 105Jkg−1)
- A. 8/3.3kg
- B. 3.3/80kg
- C. 80/33kg
- D. 3.3/8kg
33. The equation of a wave traveling along the positive x-direction is given by; y = 0.25 x 10 – 3 sin (500πt – 0.025x). Determine the angular frequency of the wave motion.
- A. 0.25 x 10−3rads−1
- B. 0.25 x 10−1rads−1
- C. 5.00 x 102rads−1
- D. 2.50 x 103rads−1
34. If a sound wave goes from a cold air region to a hot air region, its wavelength will——
- A. increase
- B. decrease
- C. decrease then increase
- D. remain constant
35. The lowest note emitted by a stretched string has a frequency of 40Hz. How many overtones are there between 40Hz and 180Hz?
- A. 4
- B. 3
- C. 2
- D. 1
36. A man stands 4m in front of a plane mirror. If the mirror is moved 1m towards the man, the distance between him and his new image is—–
- A. 3m
- B. 5m
- C. 6m
- D. 10m
37. The inside portion of part of a hollow metal sphere of diameter 20cm is polished. The portion will therefore form a
- A. concave mirror of focal length 5cm
- B. concave mirror of focal length 10cm
- C. convex mirror of focal length 5cm
- D. convex mirror of focal length 10cm
38. The velocities of light in air and glass are 3.0 x 108ms−1and 2.0 x 108ms−1 If the angle of refraction is 30º, the sine of the angle of incidence is
- A. 0.33
- B. 0.50
- C. 0.67
- D. 0.75
39. An astronomical telescope is said to be in normal adjustment when the——
- A. eye is accommodated
- B. focal length of an object lens is longer than that of eye piece
- C. final image is at the near point of eye
- D. final image is at infinity
40. A 2H inductor has negligible resistance and is connected to a 50πHz A.C supply. The reactance of the inductor is?
- A. 200Ω
- A. 50Ω
- C. 100/π
- D. 25/Πω
