Current Electri...

Three moving coil galvanometers A ,B and C are made of coils of three different material having torsional constant 1,8 × 10^-8 , 2.8 × 10^-8 and 3.8 × 10^-8 , respectively. If the three galvanometers are identical in all other respect, then in which of the above cases sensitivity is maximum ?

In a meter bridge a 30Ω resistance is connected in the left gap and a pair of resistances P and Q in the right gap. Measured from the left, the balance point is 37.5 cm, when P and Q are in series and 71.4 cm when they are parallel. The values of P and Q (in ohm) are

If resistance of voltmeter is 10000 Ω and resistance of galvanometer is 2 Ω, then find R when voltmeter reads 12V and galvanometer reads 0.1 A .

Electrons are emitted by a hot filament and are accelerated by an electric field E as shown in fig. The two stops at the left ensure that the electron beam has a uniform cross-section.

A metallic block has no potential difference applied across it, then the mean velocity of free electrons at absolute temperature T is

A potential difference of V is applied at the ends of a copper wire of length l and diameter d. On doubling only d, the drift velocity.

A current through a wire depends on time as I = 10 + 4t. The charge crossing through the section of the wire in 10 seconds is

There are two concentric spheres of radius a and b respectively. If the space between them is filled with medium of resistivity ρ, then the resistance of the intergap between the two spheres will be

A given corbon resistor has the following colour code of the various strips : Orange, red, yellow and gold. The value of resistance in ohm is

Variation of current (I) and voltage (V) in a conductor has been shown in Fig. The resistance of the conductor is