Infra-red thermometers work by detecting the 

The efficiency of a cell with internal resistance of 2\(\Omega\) supply current to a 6\(\Omega\) resistor is 

Which of the following measuring instruments operates based on the heating effect of electric current?

What is the colour of red rose under a blue light?

Calculate the value of electric field intensity due to a charge of 4μC if the force due to the charge is 8N