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

A wavefront is a surface

When the tension in string is increased by $3 \mathrm{~kg} \omega \mathrm{t}$, the frequency of the fundamental mode increases in the ratio $2: 3$. The initial tension in the string is