2010 - WAEC Physics Past Questions and Answers - page 3
An electric drill rated 400W is used to drill a hole in copper of mass 400g in 20s. Calculate the rise in temperature if all the heat produced is absorbed by the copper. [specific heat capacity of copper = 400Jkg-1K-1]
A solid of mass 0.5kg initially at 50oC melts at 60oC. Calculate the quantity of heat required to melt it completely. [specific heat capacity of the solid =2.0KJ kg-1K-1][Specific latent heat of fusion of solid =1.0 KJ kg-1]
Dew point is not affected by
A certain wave has a speed of 20ms-1. If the frequency of the wave is 0.25Hz, calculate the distance between successive crests of the wave
The ability of a wave to spread around corners is called
The following devices use plane mirrors in their operations, except
When an object is placed at the principal focus of a concave mirror, the location of the image formed is
From the diagram, the correct equation for the refractive index n of the medium is
A ray of light travels from air to water. The refeactive index of water is given by the expression
A lens that is thinner at the middle and thicher at the edges is