A/L 2001 Physics MCQ - Questions 31 - 40

31. A steal razor blade can be made to stay on the surface of water. Consider the following statements regarding this.
1. (A) Staying of the steel razor blade on the surface of water contradicts the Archimedes principle because there is no upthrust acting on the blade.
2. (B) The steal razor blade is kept on the surface of water by the forces due to the surface tension of water.
3. (C) Adding soap to water would cause the steel razor blade to sink because soap reduces the surface tension of water.
4. Of the above statements,
5. 
   
1. (1) only (A) is true
2. (2) only (B) is true
3. (3) only (C) is true
4. (4) only (A) and (B) are true
5. (5) only (B) and (C) are true
6. Answer with explanation
32. Air
    
    flows through the tube PQ at a constant rate. Two ping-pong balls are levitated in equilibrium above the tiny vertical tubes X and Y through which the air escapes. The heights of the two balls from the tube at equilibrium are h_x and h_y respectively. Which one of the following statements is true?
1. (1) If air flows from P to Q, h_x > h_y
2. (2) If air flows from P to Q, h_x = h_y
3. (3) If air flows from P to Q, h_x < h_y
4. (4) If air flows from Q to P, h_x = h_y
5. (5) If air flows from Q to P, h_x < h_y
6. Answer with explanation
33. An
    
    object moves along a horizontal circular path on the inner surface of a smooth conical shaped vessel, as shown in the figure. The force / forces acting on the object as observed by a stationary observer is / are
1. (1) weight of the object only
2. (2) weight of the object and reaction force normal to the surface only
3. (3) weight of the object and centripetal force only
4. (4) reaction force normal to the surface and centripetal force only
5. (5) centripetal force only
6. Answer with explanation
34. A wight W is hung on a tightly fixed rope as shown in the diagram.
     
    
    
    The tension in the robe is
1. (1) Approximately W
2. (2) Approximately
3. (3) less than
4. (4) in - between  and W
5. (5) much grater than W
6. Answer with explanation
35. A child of mass 20 kg is sitting on a swing of negligible mass. The swing is attached to its pivot points by two ropes, each of 3 m length. The maximum spin of the child during a swing is found to be 3 ms^-1. The maximum tension in each robe is
1. (1) 130 N
2. (2) 160 N
3. (3) 200 N
4. (4) 260 N
5. (5) 300 N
6. Answer with explanation
36. A given mass of water is in a calorimeter. When a 90 W heater is immersed in water, the temperature of water increases and comes to a steady value at 35^oC. If a 180 W heater is used, the steady temperature is 45^oC. What should be the room temperature?
1. (1) 10^oC
2. (2) 15^oC
3. (3) 20^oC
4. (4) 25^oC
5. (5) 30^oC
6. Answer with explanation
37. If an object is placed on the principal axis 31 cm from a concave mirror to the image formed is slightly smaller than the object. If the object is placed 29 cm from the mirror, the image formed is slightly larger than the object. The approximate focal length of the mirror is
1. (1) 7.5 cm
2. (2) 15 cm
3. (3) 28 cm
4. (4) 30 cm
5. (5) 32 cm
6. Answer with explanation
38. A glass cube of side 24 cm and refractive index 1.5 contains a small air bubble. When viewed through the block from one side, the air bubble appears to be 12 cm from that side. When viewed from the opposite side, how far will the air bubble appear from that side?
1. (1) 16 cm
2. (2) 12 cm
3. (3) 8 cm
4. (4) 6 cm
5. (5) 4 cm
6. Answer with explanation
39. A rocket carries 1.8 x 10⁴ kg of liquid oxygen in a vertical tank of cross section 3.0 m². At the lift-off the rocket accelerates vertically upward at 2.0 ms^-1 relative to the earth. The pressure on the bottom of the tank at the lift-off is
1. (1) 1.2 x 10³ N m^-2
2. (2) 7.2 x 10³ N m^-2
3. (3) 1.2 x 10⁴ N m^-2
4. (4) 6.0 x 10⁴ N m^-2
5. (5) 7.2 x 10⁴ N m^-2
6. Answer with explanation
40. A
    
    uniform bar of mass M is suspended from its midpoint by a spring balance. Two masses m₁ and m₂ (m₂ > m₁) are placed at the two end of the bar. A wedge supports the bar at the end B to keep it horizontally as shown in the figure. The reading of the spring balance is
1. (1) 0
2. (2) m₁g
3. (3) (M + m₁)g
4. (4) (M + 2m₁)g
5. (5) (M + m₁ + m₂)g
6. Answer with explanation

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A/L 2001 Physics MCQs: 1 - 10 | 11 - 20 | 21 - 30 | 31 - 40 | 41 - 50 | 51 - 60