Bihar Police Constable Model Paper 4

CONCEPT:

• When an electric current is passed through a conductor, the conductor becomes hot after some time and produce heat.
• This happens due to the conversion of some electric energy passing through the conductor into heat energy. This effect of electric current is called the heating effect of the current or Joule heating effect.
• The appliances based on the heating effect of electric current work on both AC and DC supply.
• The amount of heat liberated can be given as
• H = $\frac{\mathit{P}\mathit{t}}{4.2}$ cal ⇒ H = W = Pt = ${\mathit{I}}^2\mathit{R}$ joule
• Electric current passing through conductor = IT
• The power dissipated across copper coil = P
• Work done by current = W
• The resistance of wire = R
• Heat dissipated because of current = H
• time period = t
• CALCULATION:
• Heat generation = P × t
• Heat generation = ${\mathit{I}}^2$ × R × t
• Where I = Current
• R = resistance
• t = time
• Heat generation = ${\left(0.1\right)}^2$ × 1000 × 25
• = 250 J