Electricity Tes...

5,000 alpha particles per minute are passing through a straight tube of radius r. The resulting electric current is (approximately)

A wire has a resistance of 1 . It is stretched to double its length. The resistance of the wire will be

On stretching a wire, its radius decreases by 1%. The resistance will

Four equal resistances are connected as shown in the figure. The resistance measures across AB will be

Seven identical lamps of resistance 2200 each are connected to 220 V line as shown in the figure. What will be the reading on the ammeter?

An electric bulb is designed to draw P₀ power and V₀ voltage. If the voltage is V, it draws P power. Which of the following relations holds true?

You have the following appliances each of 500 W, running on 220 V AC:

(i) An electric iron
(ii) An electric toaster
(iii) An electric room heater

The electrical resistance is

Two heating coils, one of fine wire and the other of thick wire of the same material and of the same length, are connected in series and in parallel. Which of the following statements is correct?

Two electric bulbs A and B are designed for the same voltage. Their power ratings respectively are P_A and P_B, with P_A > P_B. If they are joined in series across a V-volt supply, then

An ammeter and a voltmeter are joined in series to a cell. Their readings are A and V, respectively. If a resistance is now joined in parallel with the voltmeter, then

A galvanometer is used to measure small currents. A certain galvanometer has a resistance 500 and gives a full-scale deflection for a current of 200 µA. This meter is connected as shown in the figure to make a multi-range current meter. Connection to the circuit is made at the terminals as shown.



The values of current in the external circuit needed to give full-scale deflections when X is connected to A, B and C in turn are shown in the table:

How many turns of a nichrom wire, 1mm in diameter, should be wound around a porcelain cylinder with radius 2.5 cm to obtain a heater with resistance of 20 ohms. (Given (Nichrome) = 1.0 × 10^-6 )

The heat energy produced by the coil in the given circuit in five minutes is

A uniform conductor of resistance 'R' is cut into 20 equal pieces. Half of them are joined in series and remaining half of them are connected in parallel. If two combinations are joined in series, the effective resistance of all pieces is

A circuit is shown in the figure. If the switch 'S' is closed, the current in the ammeter

If the current flowing in a coil of resistance 90 is to be reduced to 90%, what value of resistance should be connected in series with it?

The magnitude of l in amperes is

A current of 6 A enters one corner P of an equilateral triangle PQR having three wires of resistances 2 Ω each and leave by the corner R. Then, l₁ and l₂ respectively are:

If you are provided three resistances of 2Ω, 3Ω and 6Ω, how will you connect them so as to obtain the equivalent resistance of 4?

By using only two resistance coils singly, in series or in parallel, one should be able to obtain resistances of 3, 4, 12 and 16 ohms. The separate resistances of the coil are