An electric fan and a heater are marked as $$100\,W, 220\,V$$ and $$1000\,W, 220\,V$$ respectively. The resistance of heater is
A.
equal to that of fan
B.
lesser than that of fan
C.
greater than that of fan
D.
zero
Answer :
lesser than that of fan
Solution :
As $$R \propto \frac{{{V^2}}}{P}$$ or $$R \propto \frac{1}{P},$$ so resistance of heater is less than that of fan.
Releted MCQ Question on Electrostatics and Magnetism >> Electric Current
Releted Question 1
The temperature coefficient of resistance of a wire is 0.00125 per $$^ \circ C$$ At $$300\,K,$$ its resistance is $$1\,ohm.$$ This resistance of the wire will be $$2\,ohm$$ at.
The electrostatic field due to a point charge depends on the distance $$r$$ as $$\frac{1}{{{r^2}}}.$$ Indicate which of the following quantities shows same dependence on $$r.$$
A.
Intensity of light from a point source.
B.
Electrostatic potential due to a point charge.
C.
Electrostatic potential at a distance r from the centre of a charged metallic sphere. Given $$r$$ < radius of the sphere.