Current Electricity · Question 30

A wire of length 25 m and cross-sectional area 5 mm2 having resistivity of 2 10-6 m is bent into a complete circle. The resistance between diametrically opposite points will be

1. 100
2. 2.5
3. 12.5
4. 50

In the figure shown below, a resistance of 150.4 is connected in series to an ammeter A of resistance 240 . A shunt resistance of 10 is connected in parallel with the ammeter. The reading of the ammeter is mA. [figure]

A motor operating on 100 V draws a current of 1 A. If the efficiency of the motor is 91.6\%, then the loss of power in units of cal/s is

1. 6.2
2. 2
3. 8.4
4. 4

Two cells of emfs 1 V and 2 V and internal resistances 2 and 1 , respectively, are connected in series with an external resistance of 6 . The total current in the circuit is I1. Now the same two cells in parallel configuration are connected to same external resistance. In this case, the total current drawn is I2. The value of ( I1I2 ) is x3. The value of x is .

The battery of a mobile phone is rated as 4.2 V, 5800 mAh. How much energy is stored in it when fully charged?

1. 87.7 kJ
2. 43.8 kJ
3. 48.7 kJ
4. 24.4 kJ

Find the equivalent resistance between two ends of the following circuit [figure]

1. r
2. r6
3. r3
4. r9

A wire of resistance R is bent into an equilateral triangle and an identical wire is bent into a square. The ratio of resistance between the two end points of an edge of the triangle to that of the square is

1. 8/9
2. 9/8
3. 32/27
4. 27/32

The value of current I in the electrical circuit as given below, when potential at A is equal to the potential at B, will be A. [figure]