The material used to slow down the neutrons in a nuclear reactor is 
 

Which of the following statements explain why hot soapy water is more effective in cleaning oil-stained dishes?

The diagram above illustrates a beam of parallel rays from a distant object O, incident on one side of the total reflecting prism. Which diagram does not represent the correct path of the beam when it emerges from the prism?

An electrical device has 50 turns in its primary coil  and 20 turns in the secondary coil. The device can be a\an?

The earpiece of a telephone handset converts energy from