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The ratio of the lengths densities masses and resistivities of two wires A and B are 1: 2 1: 2 1:1 1: 4 respectively. The ratio of their resistance are:
he length of a conductor is halved. Its conductance will be:
The resistances in left and right gaps of a metre bridge are 4 and 6 ohm. The balance point is obtained at
When cells are connected in series:
Two cells of 1.25 V and 0.75 V are connected in parallel. The effective voltage is:
Which of the following has the maximum resistance?
An electric current is passed through a circuit containing two wires of the same material connected in parallel. If the lengths and radii of the wires are in the ratio of 4/3 and 2/3 then the ratio of the currents passing through the wire will be:
The length of a given cylindrical wire is increased by 100%. Due to the consequent decrease in diameter the change in the resistance of the wire will be:
A voltmeter can be constructed from a moving coil galvanometer by:
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To convert a galvanometer into voltmeter one should connect:
The resistance of the series combination of two resistances is S. When they are joined in parallel the total resistance is P. If S = nP then the minimum possible value of n is:
The sensitivity of a potentiometer can be increased by:
For accurate measurements the resistance of a voltmeter should be:
A big dry cell A and a small dry cell B have the same emf. The internal resistance of A:
A wire of resistance R is stretched so that its length increases by 10%. The resistance of the wire increases by:
Steady current flows in a metallic conductor of non-uniform cross-section. The quantity constant along the length of the conductor is:
When battery and galvanometer are interchanged in the case of Wheatstone bridge then:
Two identical resistors are connected in parallel then connected in series The effective resistance are in the ratio:
To use a moving coil galvanometer as an ammeter one must connect:
Which of the following is likely to have the largest resistance?
o convert a galvanometer into an ammeter we should connect:
Overloading of an electric circuit implies:
Two resistances are connected in parallel and a current is sent through the combination. The current divides itself:
By increasing the temperature the specific resistance of a conductor and a semiconductor:
If an ammeter is to be used in place of a voltmeter then we must connect with the ammeter a:
The thermistors are usually made of:
When cells are arranged in parallel
An ammeter of resistance 0.16 ohm is shunted with a resistance of 0.04 ohm which gives a reading of 8 A. The current in the main circuits is
he sequence of bands on carbon resistor is brown black brown and gold the value of resistance is either
A voltmeter 100 V range is of 9000 ohm resistance and another voltmeter of range 80 V has a resistance of 11000 ohms. This combination is connected across 120 V. The reading of voltmeter of 100 V range will be
The e.m.f. of a cell is E when connected across a resistor R the P.D. between the terminals is V. The internal resistance of the cell is given by
With a cell of e. m. f. 1.5 V the balancing point is obtained at a distance of 60 cm from one end of a potentiometer wire. Find the p.d. between the two ends of the wire if its total length is 1 m.
When cells are connected in series
A cell of e. m. f. E is connected across resistance R. The potential difference between the terminals of a cell is found to be V. The internal resistance of the cell must be
Mixed groups of cells will send the maximum current in the external circuit when total internal resistance is
A battery of e. m. f. E and internal resistance r is being charged with current i. The terminal potential will be
In a closed circuit the e.m.f. and internal resistance of a battery are E and R respectively. If an external resistance R is connected to the battery the current flowing through the circuit shall be
A voltmeter reading up to 1000 m V is calibrated with a potentiometer. An e. m. f. of 1.08 V is balanced across 5.4 m of the wire. The balanceing length is 4.55 m when the voltmeter reads 0.9 V. The error in the voltmeter reading is
A voltmeter 100 V range is of 9000 ohm resistance and another voltmeter of range 80 V has a resistance of 11000 ohms. This combination is connected across 120 V.The reading of voltmeter having resistance 11000 ohm is
The current from the battery in the above circuit is
A 20 ohm resistance with an unknown resistance R in series is connected to the potentiometer arrangement having a constant current in its main circuit. If p. d. across 2 ohm resistance is balanced at 300 cm length and p. d. across R at 360 cm length then R is
Two identical resistors are connected in parallel then in series. The effective resistances are in the ratio
A bettery of e.m. f. E and in internal resistance r is being used and is supplying current i in the circuit. The terminal potential will be
A voltmeter reading up to 1000 m V is calibrated with a potentiometer. An e. m. f. of 2.08 V is balanced across 8.4 m of the wire. The balancing length is 3.68 m when the voltmeter reads 0.9 V. The error in the voltmeter reading is
A wire of resistance R is stretched so that its length increases by 10%. The resistance of the wire increases by
The plates of a capacitor are charged to a potential difference of V volts and then connected across a resistor. After one second the potential difference between the plates is V/3 then after 2 sec. from the start the potential difference between the plates is
When the cells of different e. m. fs. and internal resistances are connected in parallels
If internal resistance of cells is large as compared to the external resistance then the cells should be connected in
The potential gradient along the length of a uniform wire is 5 V per metre. There at two points A and B on the wire which are 20 cm and 80 cm on the metre scale fitted along the wire. The p. d. between them will be
A circuit whose resistance is R is connected to n similar cells. If the current in the circuit is the same whether the cells are connected in series or in parallel then the internal resistance r of each cell is given by
An ammeter of resistance 0.16 ohm shunted with a resistance of 0.04 ohm gives a reading of 8 A. The current in the main circuit is