Waec Physics Past Questions For Year 1989
Question 16
Calculate the heat energy required to vapourize 50g of water initially at 80oC if the specific heat capacity of water is 4.2Jg-1K (specific latent heat of vapourization of water is 2260Jg-1).
- A. 533000J
- B. 230000J
- C. 117200J
- D. 113000J
- E. 4200J
Question 17
Which of the following substance is not a good conductor of electricity?
- A. Human body
- B. Glass
- C. Aluminium
- D. Earth
- E. Copper
Question 18
Water in an open container boils at a lower temperature when heated at the top of a mountain than at sea-level because at the top of a mountain the
- A. relative humidity is higher than at sea-level
- B. rays of the sun adds more heat to the water
- C. temperature is lower than that at sea-level
- D. pressure is lower than that at sea-level
- E. pressure is more than that at sea-level
Question 19
The refractive index of a given transparent medium is 1.4. Which of the following is the minimum internal angle for total internal reflection to take place in the medium?
- A. 30o
- B. 36o
- C. 44o
- D. 46o
- E. 54o
Question 20
The image in a pine-hole camera is always
- A. diminished
- B. enlarged
- C. upright
- D. inverted
- E. blurred
