DC and AC Potentiometer

Q. A dc potentiometer is designed to measure upto 2 V with a slide wire of 1000 mm. A standard cell of emf 1.5 V obtains balance at 800 mm. A test cell is seen to obtain balance at 750 mm. Which of these statement(s) is/are correct?

1. Emf of test cell is 1.4062 volt
2. The sensitivity of potentiometer is 0.005 V/mm
3. Potentiometer works on principle of potential divider
4. Potentiometer is not accurate.

Q. A potentiometer is basically a

1. deflection type instrument
2. null type instrument
3. deflection as well as null type instrument
4. a digital instrument

Q. In the potentiometer circuit shown in the figure, the expression for $V_x$ is

1. $(1-2\alpha )V$
2. $(1-\alpha )V$
3. $(\alpha -1)V$
4. $\alpha V$

Q. A resistance potentiometer has a total resistance of $10000\Omega$ and is rated 4 W. If the range of potentiometer is 0 to 100 mm, then its sensivity in V/mm

1. 1.0
2. 2.0
3. 2.5
4. 25

Q. A simple slide wire potentiometer is used for measurement of current in the circuit. The voltage drop across a standard resistor of 0.5 $\Omega$ is balanced at 100 cm. The magnitude of current of the standard cell of 2.5 V is balanced at 50 cm is ______ A.

1. 0.1 A
2. 1 A
3. 10 A
4. 100 A

Q. In the potentiometer circuit shown in figure, balance is obtained. The unknown $E_x$ is then

1. 200 mV
2. 2.8 V
3. 3.0 V
4. 400 mV

Q. A displacement transducer with a shaft stroke of 3.0 inches, is applied to the circuit given below. The total resistance of the potentiometer is 5 $k\Omega$. The applied voltage $V_t$ is 5 V. When the wiper is 0.9 inches from B, the value of output voltage is

1. 1.5 V
2. 3.0 V
3. 0.5 V
4. 2.0 V

Q. The wiper of the $20k\Omega$ potentiometer in figure is positioned half way then the voltage $V_0$ of the circuit is

1. -1.5 V
2. -1.0 V
3. -0.75 V
4. +2.5 V

Q. A $4k\Omega ,0.02W$ potetiometer is used in the circuit shown below. The minimum value of the resistance $R_s$ in order to protect the potentiometer is

1. $2.23k\Omega$
2. $2.71k\Omega$
3. $3.82k\Omega$
4. $8.92k\Omega$

Q. A potentiometer circuit is shown in figure. The jockey of the potentiometer is kept exactly at the mid-point and the ammeter reads the current I, as 0.2 mA. When $V_x$ is reversed, the ammeter reads 3.8 mA. The internal resistance of the ammeter and the unknown potential $V_x$ are respectively

1. $500\Omega ,1.1V$
2. $500\Omega ,1.1V$
3. $500\Omega ,0.9V$
4. $50\Omega ,0.9V$