A resistor has a certain color code. If one replaces the red color by green in the code, the new resistance will be :
In a Wheatstone bridge (see fig.) , resistances P and Qare approximately equal. When R = 400, the bridge is balanced. On interchanging P and , the valueof R, for balance, is 405. The value of X is close to:
401.5 ohm
404.5 ohm
403.5 ohm
402.5 ohm
In the circuit shown, the potential difference between A and B is :
6 V
2 V
3 V
1 V
In the experimental set up of metre bridge shown in the figure , the null point is obtained at a distance of 40 cm from A . If a 10 resistor is connectedin series with R_{1}, the null point shifts by 10 cm. The resistance that should be connected in parallel with (R_{1} + 10 ) such that the null point shifts back to its initial position is :
60
40
20
30
the resistance of meter bridge AB in given figure is . With the cell of emf and rehostat resistance R_{h} = the null point is obtained at some point J. When the cell is replaced by another one of emf the same null point J is found for . The emf is:
0.6 V
0.4 V
0.3 V
0.5 V
Two equal resistance when connected in series to a battery, consume electric power of 60W. If these resistance are now connected in parallel combination to the same battery, the electric power consumed will be:
120W
240 W
30 W
60 W
The charge on a capacitor plate in a circuit, as a function of time, is shown in the figure :
What is the value of current at t = 4 s ?
2
3
zero
1.5
In the given circuit diagram, the currents, I_{1} = -0.3 A, I4 = 0.8 A and I5 = 0.4 A, areflowing as shown. The currents I2 , I3 and I6 ,respectively, are :
-0.4 A, 0.4 A, 1.1 A
1.1 A -0.4 A, 0.4 A
0.4 A,1.1 A ,0.4 A
1.1 A ,0.4 A,0.4 A
A galvanometer , whose resistance is 50 ohm , has 25 divisions in it. When a current of 4 X 10^{-4} A passes through it , its needle (pointer) deflects by one division. To use this galvanometer as a voltmeter of range 2.5 V , it should be connected to a resistance of :
200 ohm
6200 ohm
250 ohm
6250 ohm
A current of 2 mA was passed through an unknown resistor which dissipated a power of 4.4 W. Dissipated power when an ideal power supply of 11 V is connected across it is :
The actual value of resistance R, shown in the figure is 30 . This is measured in an experiment as shown using the standard formula , Where are the reading of the voltmeter and ammeter, respectively. If the measured value of R is 5% less, then the internal resistance of the voltmeter is:
The Wheatstone bridge shown in the figure here, get balance when the carbon resistor used as R_{1} has the colour code (Orange, Red, Brown) The resistor R_{2} and R_{4} are 80 and 40, respectively.
Assume that the colour code for the carbon resistor, used as R_{3} ,would be :
Brown, Blue, Brown
Brown, Blue, Black
Red, Green, Brown
Grey, Black, Brown
In the given circuit the cells have zero internal resistance. The currents (in Amperes ) Passing through resistance and respectively, are :
1,2
2,2
0.5,0
0, 1
A 2 W carbon resistor is color-coded with green, black, red and brown respectively. The maximum current which can be passed through this resistor is :
20 mA
100 mA
0.4 mA
63 mA
A uniform metallic wire has a resistance of 18 and is bent into an eqilateral triangle. Then, the resistance between any two vertices of the triangle is:
4
8
12
2
A potentiometer wire AB having length Land resistance 12r is joined to a cell Dof emf and internal resistance r. A cell Chaving emf and internal resistance 3r is connected. The length AJ is connected with the galvanometer as shown in the fig. shows no deflection is:
In the given circuit the internal resistance of the 18V cell is negligible. If R_{1} = 400, R_{3} = 100 and R_{4} = 500 and the reading of an ideal voltmeter across R_{4 }is 5V, then the value of R_{2 }will be:
450
300
550
230
The galvanometer deflection , when key K_{1} is closed but K_{2} is open, equals (see figure). On closing K_{2} also and adjusting R_{2} to 5 , the deflection in galvanometer becomes . The resistance of the galvanometer is then , given by [ Neglect the internal resistance of battery ] :
5
12
25
22
A carbon resistance has a following colour code. What is the value of resistance?
%
%
%
%
Two electric bulbs, rated at (25 W, 220 V) and (100 W,220 V ) are connected in seriees across a 220 V voltage source. If the 25 W and 100 W bulbs draw powers P_{1} and P_{2} respectively, then :
P_{1} = 16 W , P_{2} = 4 W
P_{1} = 4 W , P_{2} = 16 W
P_{1} = 16 W , P_{2} = 9 W
P_{1} = 9 W , P_{2} = 16 W