Current Electricity and Electrical Instrument Questions

The internal resistance of a 2.1 V cell which gives a current of 0.2 A through a resistance of 10 Ω is

A coil is self-inductance L is connected in series with a bulb B and an AC source. Brightness of the bulb decreases when :

The resistances of the four arms P,Q, R and S ina Wheatstone′s bridge are 10 ohm, 30 ohm, 30 ohmand 90 ohm, respectively. The e.m.f. and internalresistance of the cell are 7 volt and 5 ohmrespec...

In a large building, there are 15 bulbs of 40 W, 5 bulbs of 100 W, 5 fans of 80 W and 1 heater of 1 kW. The voltage of the electric mains is 220 V. The minimum capacity of the main fuse of the buildin...

During an experiment with a metre bridge, the galvanometer shows a null point when the jockey is pressed at 40.0 cm using a standard resistance of 90 Ω, as shown in the figure. The least count of...

Two cities are 150 km apart. Electric power is sent from one city to another city through copper wires. The fall of potential per km is 8 volt and the average resistance per km is 0.5 Ω The power...

The resistances in the two arms of the meter bridge are 5 Ω and R Ω , respectively. When the resistance R is shunted with an equal resistance, the new balance point is at 1.6 I1. The resista...

A potentiometer circuit has been set up for finding the internal resistance of a given cell. The main battery, used across the potentiometer wire, has anemf of 2.0 V and a negligible internal resistan...

In an ammeter 0.2% of main current passes through the galvanometer. If resistance of galvanometer is G, the resistance of ammeter will be

Two cells, each of e.m.f. E and internal resistance r, are connected in parallel across a resistor R. The power dissipated in the resistor is maximum if :-

In a network as shown in the figure the potential difference across the resistance 2R is (the cell has an emf of E and has no internal resistance) :...

Across a metallic conductor of non-uniform cross section a constant potential difference is applied. The quantity which remains constant along the conductor is :

A potentiometer wire has length 4 m and resistance 8Ω The resistance that must be connected in series with the wire and an accumulator of e.m.f. 2V, so as to get a potential gradient 1 mV per cm ...

A certain metallic surface is illuminated with monochromatic light of wavelength, λ. The stopping potential for photo-electric current for this light is 3V0. if the same surface is illuminated wi...

A, B and C are voltmeters of resistance R, 1.5 Rand 3R respectively as shown in the figure. Whensome potential difference is applied between X andY, the voltmeter readings are VA, VB and VCrespectivel...

A conducting square frame of side ′a′ and a long straight wire carrying current I are located in the same plane as shown in the figure. The frame moves to the right with a constant velocit...

When a current of 5 mA is passed through a galvanometer having a coil of resistance 15 Ω, it shows full scale deflection. The value of the resistance to be put in series with the galvanometer to...

Two stones are thrown up simultaneously from the edge of a cliff 240 m high with initial speed of 10 m/s and 40 m/s respectively. Which of the following graph best represents the time variation of rel...

In a common emitter transistor amplifier the audio signal voltage across the collector is 3V. The resistance of collector is 3 kΩ. If current gain is 100 and the base resistance is 2 kΩ, the voltage...

The resistance of a wire is 'R' ohm. If it is melted and stretched to 'n' times its original length, its new resistance will be :-