Physics Past Questions And Answers
A uniform cylindrical hydrometer of mass 20g and cross sectional area 0.54cm2 floats upright in a liquid. If 25cm of its length is submerged, calculate the relative density of the liquid. (Density of water = 1 gcm-3)
- A. 1.54
- B. 1.48
- C. 1.25
- D. 0.80
The core of an efficient transformer should consist of laminated pieces of metal in order to
- A. increase the heat produced by increasing the eddy current
- B. increase the heat produced by reducing the eddy current
- C. reduce the heat produced by increasing the eddy current
- D. reduce the heat produced by reducing the eddy current
An air bubble of radius 4.5 cm initially at a depth of 12 m below the water surface rises to the surface. If the atmospheric pressure is equal to 10.34 m of water, the radius of the bubble just before it reaches the water surface is
- A. 6.43 cm
- B. 8.24 cm
- C. 4.26 cm
- D. 5.82 cm
The image formed by a convex mirror is always
- A. real, erect and diminished
- B. real, inverted and diminished
- C. virtual, inverted and diminished
- D. virtual, erect and diminshed
When a body is thrown vertically upwards, its velocity at the maximum height is
- A. maximum
- B. zero
- C. double its initial value
- D. half its initial value
A man will exert the greatest pressure when he?
- A. lies flat on his back
- B. lies on his belly
- C. stands on both feet
- D. stands on the toes of one foot
Which of the following observations cannot be explained using the rectilinear propagation of light?
- A. production of images by a pinhole camera
- B. production of real images of objects by lenses
- C. formation of an annular eclipse
- D. diffraction patterns of light
Electrical appliances at home are normally earthed so that
- A. the appliances are maintained at a lower p.d than the earth
- B. both the a.c and d.c sources can be used
- C. a person touching the appliances is safe from electric shock
- D. the appliances are maintained at a higher p.d than the earth
Which of the following statements about elastic collision is correct?
- A. momentum is lost due to the sound produced
- B. loss of momentim is equal to loss in kinetic energy
- C. both kinetic energy and momentum are conserved
- D. kinetic energy is lost while momentum is conserved
A current of 10A passes through a conductor for 10s, calculate the charge flowing through the conductor
- A. 100.0C
- B. 10.0C
- C. 1.0C
- D. 0.1C