A d.c circuit can be represented by an internal voltage source of 50V with an output resistance of 100 k. In order to achieve 99 percent accuaracy for voltage measurement across its terminals, the voltage measuring devicehav a resistance of

1.  Atleast 10 M

2.  100k?

3.  atleast 10?

4.  none of these

4

Atleast 10 M

Explanation :
No Explanation available for this question

The maximum current that can be drawn from a saturated Weston cell without damaging it is

1.  100mA momentarily

2.  100µA continuously

3.  100µA memnetarily

4.  1mA momentarily

4

100µA memnetarily

Explanation :
No Explanation available for this question

The internal resistance of a saturated Weston cell is of the order of a

1.  Few ohm

2.    few kilo ohm

3.  few hundreds of ohm

4.   fraction of ohm

4

few hundreds of ohm

Explanation :
No Explanation available for this question

A 1 mA ammeter has a resistance of 100. It is to be converted to a 1 A ammeter. The value of shunt resistance is

1.  0.001

2.      0.1001?

3.   100000?

4.  100?

4

0.1001?

Explanation :
No Explanation available for this question

The decrease in the value of emf of an unsaturated Weston cell is about

1.  0        µ V per year

2.  1        mV per year

3.  5-10 µV per year

4.  30-50 µV per year

4

1        mV per year

Explanation :
No Explanation available for this question

If an analog PMMC, 0-10 A ammeter is provided with no controlling mechanision and the moving parts are free to rotate, what will be the reading of the instrument if a current of 1A (d.c) passed through the moving coil (torque produced is sufficient to overcome the frictional losses)

1.  1A

2.  10 A

3.  The pointer will continuously rotate

4.  The pointer will remain stationary

4

The pointer will continuously rotate

Explanation :
No Explanation available for this question

A voltage of 200 V produces a deflection of 900 in PMMC spring controlled instrument. If the same instruments provided with gravity control, what would be the deflection

1.  900

2.  450

3.  64.20

4.  Cannot be known from the data given

4

450

Explanation :
No Explanation available for this question

A spring producers a controlling torque of 16 × 10-6 Nm for a deflection of 1200. Suppose its width and length are made two times their original value and the thickness is halved, then value of controlling torque for the same deflection will be

1.  16 × 10-6 Nm

2.      8 × 10-6 Nm

3.   32 × 10-6 Nm

4.   2 × 10-6 Nm

4

2 × 10-6 Nm

Explanation :
No Explanation available for this question

Air friction damping should not be used where the deflection torque in the instrument is produced due to

1.  Magnetic field

2.  Electrostatic field

3.  Themo-electric emf

4.  None of these

4

None of these

Explanation :
No Explanation available for this question

Fluid friction damping can be used in

1.  Horizontally mounted instru-ment

2.  Vertically mounted instrument

3.  Both in horizontally and vertically mounted instrument

4.  None of these

4