A charged particle having drift velocity 7.5 10-4 m s-1 in an electric field of 3 10-10 V m-1 has a mobility in m2 V-1 s-1 of :
(1) 2.5 106
Mobility: = vdE
= 7.5 10-43 10-10
= 2.5 106 m2 V-1 s-1
Answer: (1)
Which of the following graph represents the variation of resistivity ( ) with temperature (T) for copper?
The solids which have the negative temperature coefficient of resistance are :
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]
In the circuits shown below, the readings of voltmeters and the ammeters will be : [figure]
Which of the following acts as a circuit protection device?
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
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?
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
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
A potentiometer is an accurate and versatile device to make electrical measurements of EMF because the method involves