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A large number of $230\Omega$ resistors are obtained by combining $120\Omega$ resistors with a standard deviation of $4.0\Omega$ and $110\Omega$ resistors with a standard deviation of $3.0\Omega$. The standard deviation of the $230\Omega$ resistors thus formed will be

1. 150

1. 2

Consider the AC bridge shown below. If $\omega RC=1and\Delta C/C<0.01,$ then the ratio $\left|\frac{V_0}{V_s}\right|$ is approximately equal to

A signal is applied at the input terminals of the circuit shown below. To attenuate the input signal by a factor of 10. The values of $R_1,C_1$ respectively are

1. 3464.1

A moving coil instrument having a resistance of $10\Omega$, gives a full-scale deflection when the current is 10 mA. What should be the value of the series resistance, so that it can be used as a voltmeter for measuring potential difference up to 100 V?

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

The two signals $S_1$ and $S_2$, shown in figure, are applied to Y and X deflection plates of an oscilloscope.



The waveform displayed on the screen is

The simultaneous application of signals $x\left(t\right)$ and $y\left(t\right)$ to the horizontal and vertical plates, respectively, of an oscilloscope, produces a vertical figure-of-8 display. If P and Q are constants and $x\left(t\right)=Psin(4t+30),$ then $y\left(t\right)$ is equal to

1. 2

1. 33.33

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

1. 2.45

1. 222

The figure shows a periodic waveform to be displayed on a CRO. A trigger setting which ensures a stationary display is

1. 588.9

An electronic voltmeter consisting of a full wave precision rectifier and an average circuit gives correct R.M.S value for square wave inputs. It's reading for a 2 V peak to peak sinusoidal input will be

An ac voltmeter uses the circuit shown below, where the PMMC meter has an internal resistance of $100\Omega$ and requires a dc current of 1 mA for full scale deflection.

Assuming the diodes to be ideal, the value of $R_s$ to obtain full scale deflection with 100 V (ac rms) applied to the input terminal would be

A double beam CRO has a bandwidth of $10MHz$. Two signals

$V_1\left(t\right)=10sin(2\pi \times 20\times {10}^{3}t)$ and

$V_2\left(t\right)=10sin(2\pi \times 20\times {10}^{6}t)$ are applied to the two channels. If $P_{1}and{P}_2$ are the peak-to-peak values of the signals displayed, then

1. 10.28

A current transformer has a single turn primary and $400$ turns on secondary winding. The resistance annd reactance of the secondary circuit are $2\Omega$ and $3\Omega$ respectively including transformer winding. When $6A$ current is flowing in the secondary winding, the magnetizing mmf is $100AT$ and iron loss is $2W$. The value of ratio error will be

1. 60

Two sinusoidal voltage signals of equal frequency are applied to the vertical and horizontal deflection plates of a CRO. The output observed on the screen is shown in the following figure. The phase difference between applied signal is

1. 250

A voltage of $6cos\left(100\pi t\right)V$ is fed as y - input to a CRO. The waveform seen on the screen of the CRO is shown in the figure. The Y and X axes settings for the CRO are respectively.

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. 0.042

For a certain dynamometer ammeter the mutual inductance M varies with deflection $\theta$ (expressed in degree) as

$M=-6cos(\theta +30°)mH$



The deflecting torque produced by a direct current of 50 mA corresponding to a deflection of 60° is

For a proving ring used in a press, the value of force and its uncertainty are given as $12355\pm 2354N$ without any rounding off. If the error should be rounded off at the maximum to two significant figure only, the value of the reading is rounded off as

The solution for the unknown resistance for a wheatstone bridge is



$R_x=\frac{R_2{R}_3}{R_1}$



where,

$R_1=100\pm 0.5\%$ $\Omega$, $R_2=1000\pm 0.5\%\Omega and$ $R_3=842\pm 0.5\%\Omega$



The range of the unknown resistance $R_x$ is

Power consumed by a balanced 3-phase, 3-wire load is measured by two wattmeter method. The first wattmeter reads twice that of the second. Then the load impedance angle in radians is

1. 0.8

1. 40

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

The primary of 400/1 A, 10 VA, 0.8 p.f, current transformer (C.T.) carries a current of 200 A. If the secondary current is measured to be 0.495 A, then the value of percentage ratio error will be

1. 0.45

1. 0.6

1. 7.34

1. 1116.02

1. 1.57

1. 0.817

A full scale deflection current of a meter is 2 mA and its internal resistance is $500\Omega$. The instrument is required to be used as voltmeter with full scale deflection of 200 V. The value of series resistor required should be

1. 0.22

1. 200

A DC ammeter has a resistance of $0.1\Omega$ and its current range is $0-100A$. If the range is to be extended to $0-500A$, then meter requires the following shunt resistance

A current transformer with a bar primary has 300 turns in its secondary winding. The resistance and reactance of the secondary circuit are $1.5\Omega$ and $1.0\Omega$ respectively including the transformer winding with 5 A flowing in the secondary winding, the phase angle error is (assuming magnetizing mmf to be 100 AT and core loss to be 1.5 W)

1. 4.5

In the a.c. bridge circuit shown in figure, at balance the parameters of the coil are calculated to be 50 mH and $20\Omega .$ Another coil is connected in parallel to the previous coil and balance is restored by changing $R_{2}to2.5k\Omega .$ The parameters of the new coil are then

The AC bridge shown in the figure is used to measure the impedance Z.



If the bridge is balanced for oscillator frequency f=2 kHz, then the impedance Z will be