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
1.6.6 ohm
2.3.6 ohm
3.3.1 ohm
4.3.0 ohm
A battery of e. m. f. E and internal resistance r is being charged with current i. The terminal potential will be
1.E
2.E + ir
3.E - ir
4.id - E
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
1.E
2.E + ir
3.E - ir
4.ir - E
A big dry cell A and a small dry cell B have the same emf. The internal resistance of A:
1.is greater than that of B
2.is equal to that of B
3.is less than that of B
4.may have any value independent of its size
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
1.(E - V) / R
2.(E - V) R
3.2(E - V) / R
4.2 (E - V) / R V
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
1.r = (R / n)
2.r = nR
3.r = R
4.r = (1 / R)
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
1.54 V
2.44 V
3.66 V
4.56 V
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
1.54 V
2.44 V
3.66 V
4.56 V
A voltmeter can be constructed from a moving coil galvanometer by:
1.shunting it with a high resistance
2.shunting it with a low resistance
3.connecting a high resistance in series with it
4.connecting a low resistance in series with it
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
1.- 0.01 V
2.zero
3.- 0.04 V
4.- 0.06 V
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
1.- 0.01 V
2.zero
3.- 0.04 V
4.- 0.06 V
A wire of resistance R is stretched so that its length increases by 10%. The resistance of the wire increases by
1.11%
2.15%
3.21%
4.28%
A wire of resistance R is stretched so that its length increases by 10%. The resistance of the wire increases by:
1.11%
2.15%
3.21%
4.28%
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
1.40 A
2.20 A
3.16 A
4.24 A
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
1.40 A
2.20 A
3.16 A
4.24 A
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:
1.3
2.1upon 3
3.8 upon 9
4.2
By increasing the temperature the specific resistance of a conductor and a semiconductor:
1.increases for both
2.decreases for both
3.decreases for both
4.increases decreases respectively
For accurate measurements the resistance of a voltmeter should be:
1.as large as possible
2.equal to the resistance across which the potential difference is to be measured
3.as small as possible
4.infinity
he length of a conductor is halved. Its conductance will be:
1.halved
2.unchanged
3.doubled
4.quadrupled
he sequence of bands on carbon resistor is brown black brown and gold the value of resistance is either
1.40 or 50
2.105 or 95
3.75 or 85
4.145 or 155
If an ammeter is to be used in place of a voltmeter then we must connect with the ammeter a:
1.low resistance in parallel
2.high resistance in parallel
3.high resistance in series
4.low resistance in series
If internal resistance of cells is large as compared to the external resistance then the cells should be connected in
1.series
2.parallel
3.partly in series and party in parallel
4.partly in series and remaining with reversed terminals.
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
1.Er / R
2.E / R + r
3.E / rR
4.ER / r
Mark correct option or options.
1.In the absence of an electric field electrons move in straight lines between collisions
2.Relaxation time is of order 10-14 second
3.Resistivity is inversely proportional to relaxation time when number of electrons per unit volume of material remains constant
4.All of the above
Mixed groups of cells will send the maximum current in the external circuit when total internal resistance is
1.less than external resistance
2.less than external resistance
3.more than external resistance
4.equal to external resistancezero
o convert a galvanometer into an ammeter we should connect:
1.a low resistance in series with it
2.a high resistance in series with it
3.a low resistance in parallel with it
4.a high resistance in parallel with it
Overloading of an electric circuit implies:
1.drawing of large current
2.connecting high resistance device
3.connecting a large number of electric devices in series with the power supply
4.none of the above
Steady current flows in a metallic conductor of non-uniform cross-section. The quantity constant along the length of the conductor is:
1.current electric field and drift speed
2.drift speed only
3.current and drift speed
4.current only
The current from the battery in the above circuit is
1.3.7 A
2.5.7 A
3.1.7 A
4.6.7 A
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
1.E - V / E
2.(E - V / E)R
3.E / E - V
4.(E / E - V)R
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:
1.200%
2.100%
3.50%
4.300%
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
1.2V / 3
2.V / 6
3.V / 9
4.V / 3
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
1.2 V
2.3 V
3.4 V
4.1 V
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:
1.1:32
2.1:16
3.8:01
4.4:01
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:
1.4
2.3
3.2
4.1
The resistances in left and right gaps of a metre bridge are 4 and 6 ohm. The balance point is obtained at
1.20 CM
2.40 cm
3.30 cm
4.25 cm
The sensitivity of a potentiometer can be increased by:
1.decreasing the length of potentiometer wire
2.increasing the length of potentiometer wire
3.increasing the emf of the cell used in primary circuit
4.all the above methods
The thermistors are usually made of:
1.metals with low temperature coefficient of resistivity
2.metals with high temperature coefficient of resistivity
3.metal oxides with high temperature coefficient of resistivity
4.semiconducting materials having low temperature coefficient of resistivit
To convert a galvanometer into voltmeter one should connect:
1.a low resistance in series with it
2.a high resistance in series with it
3.a low resistance in parallel with it
4.a high resistance in parallel with it
To use a moving coil galvanometer as an ammeter one must connect:
1.low resistance in series with the coil
2.low resistance in parallel with the coil
3.high resistance in series with the coil
4.high resistance in parallel with the coil
Two cells of 1.25 V and 0.75 V are connected in parallel. The effective voltage is:
1.0.75 V
2.2 V
3.2 V
4.2 V
Two identical resistors are connected in parallel then connected in series The effective resistance are in the ratio:
1.1:02
2.2:01
3.1:04
4.4:01
Two identical resistors are connected in parallel then in series. The effective resistances are in the ratio
1.1:02
2.2:01
3.1:04
4.4:01
Two resistances are connected in parallel and a current is sent through the combination. The current divides itself:
1.in the inverse ratio of resistances
2.in the direct ratio of resistances
3.equally in both the resistances
4.in none of the above manner
When battery and galvanometer are interchanged in the case of Wheatstone bridge then:
1.if the bridge was in adjustment before interchange it will not be in adjustment after interchange
2.if the bridge was in adjustment before interchange it will be in adjustment after interchange
3.if the bridge was in adjustment before interchange it may or may not be in adjustment after interchange
4.all of the above
When cells are arranged in parallel
1.the current capacity decreases
2.the current capacity increases
3.the e. m. f. increases
4.the e. m .f. decreases
When cells are connected in series
1.the e.m.f. increases
2.the p.d. decreases
3.current capacity increases
4.the current capacity decreases
When cells are connected in series:
1.the emf increases
2.the PD decreases
3.the current capacity increases
4.the current capacity decreases
When the cells of different e. m. fs. and internal resistances are connected in parallels
1.the e. m. f. increases in comparison with that for single cell
2.the e. m. f. decreases in comparison with that for single cell
3.the current capacity increases in comparison with that for single cell
4.the current capacity decreases in comparison with that for single cell
Which of the following has the maximum resistance?
1.Voltmeter
2.Milivoltmeter
3.Ammeter
4.Miliammeter
Which of the following is likely to have the largest resistance?
1.Moving coil galvanometer
2.An ammeter of range 1A
3.A voltmeter of range 10V
4.A copper wire of length 1 m and diameter 3 cm
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.
1.0.5 V
2.1.5 V
3.2.5 V
4.1.75 V