DC and AC Potentiometer

Q.

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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. 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 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. 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. 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. $50\Omega ,0.9V$

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 DC potentiometer is designed to measure up to 2 V with a slide wire of 800 mm. A Standard cell of emf 1.18V obtains balance at 600 mm. A test cell is seen to obtain balance at 680 mm. The emf of the test cell is

1. 1.00 V
2. 1.34 V
3. 1.50 V
4. 1.70 V

Q. A transfer instrument employed in the standardization of polar type AC potentiometer is

1. an electrostatic instrument
2. a thermal instrument
3. dynamometer instrument
4. a moving coil instrument

Q. The figure shows a potentiometer of total resistance $R_T$ with a sliding contact.

The resistance between the points P and Q of the potentiometer at the position of the contact shown is $R_C$ and the voltage ratio $V_0/V_s$ at this point is 0.5. If the ratio $R_L/R_T=1,\text{the ratio}{R}_C/R_T$ is

1. $\frac{-1+\sqrt{5}}{2}$
2. $\frac{1+\sqrt{5}}{2}$
3. $-1+\sqrt{5}$
4. $1+\sqrt{5}$

Q. A wire potentiometer of length 11 m and resistance $1\Omega /m$ balances a standard cell voltage of 1.018 V at a length of 10 m 18 cm. If the voltage of the battery supplying the current through the potentiometer is 2.0 V, then the value of the series resistance connected to the potentiometer is

1. $9\Omega$
2. $90\Omega$
3. $900\Omega$
4. $990\Omega$

Q. An unknown voltage source $E_u$ (negligible internal resistance) is connected to a potentiometer circuit as shown in the following figure. If the galvanometer current is $10\mu A$ with the direction as indicated, then value of $E_u$ is

1. 0.9910 V
2. 0.9991 V
3. 1.0012 V
4. 1.0048 V

Q. The percentage resolution of a potentiometer having number of turns equal to 5000 will be

1. 0.002%
2. 0.02%
3. 0.0002%
4. 0.2%

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. 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. The output voltage $V_0$ when the jockey of the potentiometer is exactly at the midpoint, would be

1. -4 V
2. -2.30 V
3. -2.83 V
4. -1.72 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 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.