The power dissipated in the circuit shown in
the figure is 30 Watt. The value of R is :
(1)
(2)
(3)
(4)
A cell having an emf internal resistance r is connected across a variable external resistance R. As the resistance R is increased, the plot of potential difference V across R is given by
(a)
(b)
(c)
(d)
If power dissipated in the 9 resistor in the circuit shown is 36 W, the potential difference across the 2 resistor is
1. 8 V
2. 10 V
3. 2 V
4. 4 V
A current of 2A flows through a 2 resistor
when connected across a battery. The same
battery supplies a current of 0.5 A when
connected across a 9 resistor. The internal
resistance of the battery is
(1)
(2)
(3)
(4)
In the circuit in the figure, if the potential at point A is taken to be zero, the potential at point B is :
1. -1V 2. +2V
3. -2V 4. +1V
Which one of the following bonds produces a solid that reflects light in the visible region and whose electrical conductivity decreases with temperature and has high melting point?
(1) metallic bonding
(2) van der Waals'bonding
(3) ionic bonding
(4) covalent bonding
A potentiometer circuit is set up as shown.The potential gradient across the potentiometer wire, is k volt/cm and the ammeter, present in the circuit, reads 1.0A when two way key is switched off. The balance points, when the key between the terminals (i) 1 and 2 (ii) 1and 3, is plugged in, are found to be at lengths respectively.The magnitudes, of the resistors R and X, in ohm, are then, equal, respectively, to
(a)
(b)
(c)
(d)
Consider the following two statements :
1. Kirchhoff's junction law follows from the conservation of charge.
2. Kirchhoff's loop law follows from the conservation of energy.
Which of the following is correct?
(a) Both (A) and (B) are wrong
(b) (A) is correct and (B) is wrong
3. (A) is wrong and (B) is correct
4. Both (A) and (B) are correct
1. \(0.6\pi~\Omega\)
2. \(3~\Omega\)
3. \(6\pi~\Omega\)
4. \(6~\Omega\)
A student measures the terminal potential difference \((V)\) of a cell (of emf \(\varepsilon \) and internal resistance \(r\)) as a function of the current \((I)\) flowing through it. The slope and intercept of the graph between \(V\) and \(I,\) then respectively, equal:
1. \(\varepsilon \) and \(-r\)
2. \(-r\) and \(\varepsilon \)
3. \(r\) and \(-\varepsilon \)
4. \(-\varepsilon \) and \(r\)