A parallel plate capacitor of capacitance 90 pF is connected to a battery of emf 20 V. If a dielectric material of dielectric constant K = 5/3 is inserted between the plates, the magnitude of the induced charge will be :

On interchanging the resistances, the balance point of a meter bridge shifts to the left by 10 cm. The resistance of their series combination is 1 k$$\Omega $$. How much was the resistance on the left slot before interchanging the resistances?

Two batteries with e.m.f 12 V and 13 V are connected in parallel across a load resistor of 10 $$\Omega $$. The internal resistances of the two batteries are 1 $$\Omega $$ and 2 $$\Omega $$ respectively. The voltage across the load lies between :

An electron, a proton and an alpha particle having the same kinetic energy are moving in circular orbits of radii r_e, r_p, r$$_\alpha$$ respectively in a uniform magnetic field B. The relation between r_e, r_p, r$$_\alpha$$ is: