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

A wire of resistance $12 {\mathrm{\Omega m}}^{-1}$ is bent to form a complete circle of radius 10 cm. The resistance between its two diametrically opposite points, A and B as shown in the figure, is :

(a) $0.6 \mathrm{\pi } \mathrm{\Omega }$                                               (b) $3 \mathrm{\Omega }$

(c) $6 \mathrm{\pi } \mathrm{\Omega }$                                                  (d) $6 \mathrm{\Omega }$

See the electrical circuit shown in this figure. Which of the following equation is a correct equation for it?

1. ${\epsilon }_1-\left(i_1+i_2\right)R-i_1{r}_1=0$

2. ${\epsilon }_2-i_2{r}_2-{\epsilon }_1-i_1{r}_1=0$

3. $-{\epsilon }_2-\left(i_1+i_2\right)R+i_2{r}_2=0$

4. ${\epsilon }_1-\left(i_1+i_2\right)R+i_1{r}_1=0$

A wire of a certain material is streched slowly by ten per cent. Its new resistance and specific resistance become respectively 

(1) 1.2 times, 1.1 times

(2) 1.21 times,same 

(3) both remain the same

(4) 1.1 times, 1.1 times

An electric kettle takes 4 A current at 220 V. How much time will it take to boil 1 kg of water from temperature ${20}^{°}$C? The temperature of boiling water is ${100}^{°}$C

(a) 6.3 min

(b) 8.4 min

(c) 12.6 min

(d) 4.2 min

A cell can be balanced against 110cm and 100 cm of potentiometer wire, respectively with and without being short-circuited through a resistance of $10 \Omega$. Its internal resistance is 

(1) 1.0 $\Omega$

(2) 0.5 $\Omega$

(3) 2.0 $\Omega$

(4) zero 

In the circuit shown, the current through the 4 $\Omega$resistor is 1 A when the points P and M are connected to a DC voltage source. The potential difference  between the points M and N is 

1. 1.5 V 

2. 1.0 V

3. 0.5 V 

4. 3.2 V

A milliammeter of range 10 mA and resistance 9$\Omega$ is joined in a circuit as shown in Fig. 6.57. The meter gives full-scale deflection for current I when A and C are used as its terminals if current enter at A and leaves at C (B is left isolated). The value of I is :

(1)100 mA

(2) 900 mA

(3) 1 A

(4) 1.1 A

A candidate connects a moving coil voltmeter V, a moving coil ammeter A, and a resistor R as shown in Fig. 6.58. If the voltmeter reads 20 V and the ammeter reads 4 A, R is 

(1) equal to 5 $\Omega$

(2) greater than 5 $\Omega$

(3) less than 5 $\Omega$

(4) greater or less than 5 $\Omega$ depending upon its material.

A voltmeter has a resistance of G ohm and range V volts. The value of resistance used in series to convert it into a voltmeter of range nV volts is :

(1) nG

(2) (n-1)G

(3) G/n

(4) G/(n-1)