Current Electricity · Question 36

Which of the following graph represents the variation of resistivity ( ) with temperature (T) for copper?

1. [figure]
2. [figure]
3. [figure]
4. [figure]

The solids which have the negative temperature coefficient of resistance are :

1. insulators only
2. semiconductors only
3. insulators and semiconductors
4. metals

Six similar bulbs are connected as shown in the figure with a DC source of emf E, and zero internal resistance. The ratio of power consumption by the bulbs when (i) all are glowing and (ii) in the situation when two from section A and one from section B are glowing, will be : [figure]

1. 4 : 9
2. 9 : 4
3. 1 : 2
4. 2 : 1

In the circuits shown below, the readings of voltmeters and the ammeters will be : [figure]

1. V1 = V2 and i1 = i2
2. V1 > V2 and i1 > i2
3. V1 > V2 and i1 = i2
4. V1 = V2 and i1 > i2

Which of the following acts as a circuit protection device?

1. inductor
2. conductor
3. switch
4. fuse

A set of n equal resistors, of value R each, are connected in series to a battery of emf E and internal resistance R. The current drawn is I. Now, the n resistors are connected in parallel to the same battery. Then the current drawn from battery becomes 10I. The value of n is

1. 10
2. 11
3. 20
4. 9

A battery consists of a variable number n of identical cells (having internal resistance r each) which are connected in series. The terminals of the battery are short-circuited and the current I is measured. Which of the graphs shows the correct relationship between I and n?

1. [figure]
2. [figure]
3. [figure]
4. [figure]

A carbon resistor of (47 4.7) k is to be marked with rings of different colours for its identification. The colour code sequence will be

1. Violet – Yellow – Orange – Silver
2. Yellow – Violet – Orange – Silver
3. Yellow – Green – Violet – Gold
4. Green – Orange – Violet – Gold

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

1. Rn
2. n2R
3. Rn2
4. nR

A potentiometer is an accurate and versatile device to make electrical measurements of EMF because the method involves

1. potential gradients
2. a condition of no current flow through the galvanometer
3. a combination of cells, galvanometer and resistances
4. cells