Question 2 :
In a potentiometer experiment the balancing with a cell is at length $240$ cm. On shunting the cell with a resistance of $2\Omega$ the balancing length becomes $120$cm. The internal resistance of the cell is?
Question 3 :
A $3hp$ motors requires $2.4 kw$ to drive it; its efficiency is about:<br/>
Question 4 :
The current carrying wire and the rod $AB$ are in the same plane. The rod moves parallel to the wire with a velocity $v$. Which one of the following statement is true about induced e.m.f. in the rod?
Question 5 :
Assertion: The kinetic energy of electrons in a metallic wire will increase, if the temperature of the wire is increased
Reason: On increasing temperature, conductivity of metallic wire decreases
Question 6 :
A potentiometer wire of length $10\ m$ and resistance $10\Omega$ per metre is connected in series with a resistance  box and a $2\ volt$ battery. If a potential difference of $100\ mV$ is balanced across the whole length of potentiometer  wire, then the resistance introduced in the resistance box will be:
Question 8 :
In the series combination of n cells each cell having emf $\varepsilon$ and internal resistance r. If three cells are wrongly connected, then total emf and internal resistance of this combination will be.
Question 9 :
For driving current of $2A$ for $6$ minute in a circuit. $1000 J$ of work is to be done. The e.m.f. of the source in the circuit is<br>
Question 10 :
Which color band in the color coding of aresistor has the multiplier $10^{-1}$?
Question 11 :
A potentiometer wire of length $200$cm has a resistance of $20\Omega$. It is connected in series with a resistance of $10\Omega$ and an accumulator of emf $6$V having negligible internal resistance. A source of $2.4$V is balanced against a length L of the potentiometer wire. The value of L is?
Question 12 :
Electrical power P is given by the expression  P = $\dfrac{Q \times V}{t}$. time. What does $Q$ and $V$ stand for?
Question 13 :
The terminal potential difference of a cell is equal to the emf of the cell when:
Question 14 :
A transformer with turns ratio $\dfrac{N_1}{N_2}=\dfrac{50}{1}$ is connected to a $120$ volt AC supply. If primary and secondary circuit resistance are $1.5k\Omega$ and $1\Omega$ respectively then find out power out put.
Question 15 :
The resistance of a wire is 50 ohm. Then the graph between $\log V$ and $\log I$ is :-
Question 16 :
When a battery connected across a resistor of $16 \Omega$, the voltage across the resistor is $12 V$. When the same battery is connected across a resistor of $10 \Omega$, voltage across it is $11 V$. The internal resistance of the battery (in $ohm$) is:
Question 17 :
Two cells of same emf are connected in series. Their internal resistances are $r_1$ and $r_2$ respectively and $r_1 > r_2$. When this combination is connected to an external resistance R then the potential difference between the terminals of first cell becomes zero. In this condition the value of R will bw<br>
Question 19 :
Assertion : A series combination of cells is used when their internal resistance is much smaller than the external resistance.<br/>Reason : It follows from the relation $I=\dfrac{nE}{R+nr}$, where the symbols have their standard meaning.<br/>
Question 20 :
Assertion: The temperature coefficient of resistance is always positive
Reason: On increasing the temperature the resistance of metals and alloys increase
Question 21 :
The specific resistance of a rod of copper as compared to that of thin wire of copper is
Question 22 :
The potentiometer wire $10\ m$ long and $20\ ohm$ resistance is connected to a $3\ volt$ emf battery and a $10\ ohm$ resistance. The value of potential gradient in $volt/m$ of the wire will be
Question 23 :
A 30V-90W lamp is operated on a 120 V DC line. A resistor is connected in series with the lamp in order to glow it properly. The value of resistance is
Question 24 :
Two wires of same metal have the same length but their cross-sections area in the ratio 3 : 1. They are joined in series. The resistance of the thicker wire is $10\Omega$ .The total resistance of the combination will be:<br/>
Question 25 :
A potnetiometer wire, 10 m long, has a resistance of 40 $\Omega$. It is connected in series with a resistance box and a 2 V storage cell. If the potential gradient along the wire is 0.1 m V/cm, the resistance unplugged in the box is:
Question 26 :
An ideal battery of $4V$ and resistance $R$ are connected in series in the primary circuit of a potentiometer of length $1m$ and resistance $5\Omega$. The value of $R$, to given a potential difference of $5mV$across $10cm$ of potentiometer wire is:
Question 27 :
For a cell terminal P.D. is 2.2 V when circuit isopen and reduces to 1.8 V when cell is connectedto a resistance of R = 5. Determine internalresistance of cell (r) is then : -
Question 28 :
An electric circuit contains an operating heating element and a lit lamp. Which statement bestexplains why the lamp remains lit when the heating element is removed from the circuit?<br>
Question 30 :
A straight conductor of uniform cross section carries a time varying current, which varies at the rate $dI/dt = I$. If $s$ is the specific charge that is carried by each charge carrier of the conductor and $\ell$ is the length of the conductor, then the total force experienced by all the charge carriers per unit length of the conductor due to their drift velocities only is<br>
Question 31 :
A resistance of 0.01 ohms is connected in parallel with a resistance of one kilo ohm. The resistance of the combination will be:
Question 32 :
A cell of e.m.f. $\varepsilon$ and internal resistance $r$ sends current $1.0 A$ when it is connected to an external resistance $1.9\, \Omega$. But it sends current $0.5 A$ when it is connected to an external resistance $3.9\, \Omega$. Calculate the values of $\varepsilon$ and $r$.
Question 33 :
When three resistors of resistances 3,4,5 are connected in parallel, the currents through them are in the ratio<br/>
Question 34 :
Assertion: If we bend an insulated conducting wire, the resistance of the wire increases.
Reason: The drift velocity of electrons in bent wire decreases.
Question 35 :
A parallel combination of two resistors, of 1 $\Omega$ each, is connected in series with a $1.5 \Omega$ resistor. The total combination is connected across a $10\ V$ battery. The current flowing in the circuit is
Question 36 :
Three equal resistances each of 3$\Omega $ are in series and connected to a cell of internal resistance oneohm. If these resistances are in parallel andconnected to the same cell, then the ratio of therespective currents through the electric circuitsin the two cases is<br>
Question 37 :
In a circuit two or more cells of the same e.m.f. are connected in parallel in order to
Question 38 :
The voltage of clouds is $4\times10^6\;volt$ with respect to round. In a lightening strike lasting $100\;m\;sec$, a charge of $4$ coulombs is delivered to the ground. The power of lightening strike is:
Question 39 :
The length of a potentiometer wire is $l$. A cell of emf $E$ is balanced at a length $l/3$ from the positive end of the wire. If the length of the wire is increased by $l/2$. At what distance will the same cell give a balance point?
Question 41 :
Two bulbs of 250 V and 100 W are first connected in series and then in parallel with a supply of 250 V. Total power in each of the case will be respectively
Question 43 :
A wire has a resistance of $2.5$ $\Omega$ at $28$ $^oC$ and a resistance of $2.9$ $\Omega$ at $100$ $^oC$. The temperature coefficient of resistivity of material of the wire is?
Question 44 :
Assertion: A potentiometer of longer length is used for accurate measurement.
Reason: The potential gradient for a potentiometer of longer length with a given source of e.m.f. becomes small.
Question 45 :
A wire of radius r has resistance R. If it is stretched to a radius $\displaystyle\frac{r}{2}$, its resistance will be
Question 46 :
In the equation $AB = C$, A is the current density, C is the electric field, then B is
Question 47 :
If two resistances${R_1} = \left( {10.0 \pm 0.1} \right)\Omega \;and\;{R_2} = \left( {20.0 \pm 0.1} \right)\Omega \;are\;connected$ in series, then the maximum percentage error in its equivalent resistance will be
Question 48 :
A potentiometer is an accurate and versatile device to make electrical measurements of E.M.F. because the method involves:
Question 49 :
A straight conductor of uniform cross-section carries a current $I$. Let $S$ be the specific charge of an electron. The momentum of all the free electron per unit length of the conductor due to their drift velocity only, is
Question 50 :
A straight conductor of uniform cross section carries a current i. Let S be the specific charge on an electron. The momentum of all the free electrons per unit length of the conductor due to their drift velocity only is<br>
