The function of dielectric in a capacitor is

Three identical metal spheres (of same surface area) have red, black and white colors and they are heated up to same temperature. They are allowed to cool. Arrange them from maximum rate of cooling to minimum rate of cooling

In an ammeter, $4 \%$ of the main current is passing through the galvanometer, If shunt resistance is $5 \Omega$, then resistance of galvanometer will be

LC series resonant circuit produces resonant frequency ' $f$ '. If ' $L$ ' is tripled and ' $C$ ' is increased by $3 C$, the resonant frequency will be