Physics Test 74

Two metallic sphere of radii 1 cm and 2 cm are given charges 10^–2 C and 5 × 10^–2 C respectively. If they are connected by a conducting wire, the final charge on the smaller sphere is :

Find the charge on 4μF capacitor :

Find out equivalent capacitance across A & B :

The plates of a parallel plate capacitor are pulled apart with a velocity v. If at any instant their mutual distance of separation is x then magnitude of rate of change of capacitance with respect to time varies as :

Find equivalent capacitance between A and B ?

(Area of each plate = A, separation between adjacent plate = d)

In the given circuit a charge of +80μC is given to the upper plate of 4μF capacitor. Then in the steady state, the charge on upper plate of the 3μF capacitor is :

A conducting sphere of radius 10 cm is charged to 10 μC. Another uncharged sphere of radius 20 cm is allowed to touch it for sometime. After that if the sphere are separated, the surface density of charges, on the spheres will be in the ratio of :

A parallel plate capacitor of capacitance C is having charge q₀ on each plate. Now it is connected to a battery of emf V then which option is correct ?

(i) Charge supplies by battery would be CV

(ii) The outer surface of plate have equal charge q₀

(iii) The facing surface have equal and opposite charge of magnitude CV

Force acting on a proton kept between the plates of a charged capacitor is F. Now if one plate is removed then force acting on proton will become :

A thin metal plate of thickness t = d/2 is inserted between the plates of a parallel plate capacitor of capacitance C. The new capacitance will be : (d is separation between the plates)