A wheat stone bridge is used to determine the value of unknown resistance X by adjusting the variable resistance Y as shown in the figure. For the most precise measurement of X , the resistances P and Q :
Column-I gives certain physical terms associated with flow of current through a metallic conductor. Column-II gives some mathematical relations involving electrical quantities. Match Column-I and Column-II with appropriate relations.
A potentiometer wire is 100 cm long and a constant potential difference
is maintained across it. Two cells are connected in series first to
support one another and then in opposite direction. The balance points
are obtained at 50 cm and 10 cm from the positive end of the wire in the
two cases. The ratio of emf's is
A constant voltage of 50 V is maintained between the points A and B of the circuit shown in the figure. The current through the branch CD of the circuit is:
A wire of resistance R is cut into 8 equal pieces. From these pieces two equivalent resistances are made by adding four of these together in parallel. Then these two sets are added in series, The net effective resistance of combination is:
AB is a part of an electrical circuit (see figure). The potential difference \(\text{"V}_\text{A}\,-\,\text{V}_\text{B}\text{"}\), at the instant when current \(i\,=\, 2\text{A}\) and is increasing at a rate of 1 amp/second is:
The terminal voltage of the battery, whose emf is 10V and internal resistance 1Ω , when connected through an external resistance of 4Ω asshown in the figure is:
A wire of length 'l' and resistance 100Ω is divided into 10 equal parts.
The first 5 parts are connected in series while the next 5 parts are
connected in parallel. The two combinations are again connected in
series. The resistance of this final combination is:
Two heaters A and B have power rating of 1 kW and 2 kW, respectively.
Those two are first connected in series and then in parallel to a fixed
power source. The ratio of power outputs for these two cases is:
10 resistors, each of resistance R are connected in series to a battery of
emf E and negligible internal resistance. Then those are connected in
parallel to the same battery, the current is increased n times. The value
of n is
The resistance of platinum wire at \(0^\circ C\) is \(2 \Omega\) and \(6.8 \Omega\) at \(80^ \circ C\). The temperature coefficient of resistance of the wire is
Two resistors of resistance, 100 Ω and 200 Ω are connected in parallel in an electrical circuit. The ratio of the thermal energy developed in 100 Ω to that in 200 Ω in a given time is
A copper wire of length 10 m and radius \(\displaystyle \left(\frac{10{^{−2}}}{\sqrt{\pi}}\right)\) m has electrical resistance of 10 Ω. The current density in the wire for an electric field strength of 10 (V ∕ m) is
The effective resistance of a parallel connection that consists of four
wires of equal length, equal area of cross-section and same material is
0.25 Ω . What will be the effective resistance if they are connected in
series?
In a potentiometer circuit a cell of EMF 1.5 V gives balance point at 36
cm length of wire. If another cell of EMF 2.5 V replaces the first cell,
then at what length of the wire, the balance point occurs?
Three resistors having resistances r1, r2 and r3 are connected as shownin the given circuit. The ratio \(\displaystyle \frac{i_3}{i_1}\)of currents in terms of resistances usedin the circuit is
A charged particle having drift velocity of \(7.5 \times 10^{−4}\,ms^{−1}\) in an electric field of \(3 \times 10^{−10}\, V\, m^{−1}\), has a mobility in \(m^2\,V^{−1}\,s^{−1}\) of
A resistance wire connected in the left gap of a metre bridge balances a \(10\, \Omega\) resistance in the right gap at a point which divides the bridge wire in the ratio \(3 : 2\). If the length of the resistance wire is \(1.5\, m\), then the length of \(1\, \Omega\) of the resistance wire is:
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
A set of n equal resistors, of value R each, are connected in series to abattery 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 10 I . The value of n is
A battery consists of a variable number n of identical cells (havinginternal resistance r each ) which are connected in series. The terminals of the battery are short-circuited and the current I is measured. Whichof the graphs shows the correct relationship between I and n?
The charge flowing through a resistance R varies with time t as \(\text{Q}\, =\, at − bt^2\), where a and b are positive constants. The total heat produced in R is