**1.** Transformation ratio of an instrument is defined as ________

- Ratio of primary to secondary phasor
- Ratio of secondary to primary phasor
- Reciprocal of the primary phasor
- Reciprocal of the secondary phasor

**2.** The 1000/5 A 50 Hz ring cored current converter has a bar primary. The secondary resistor (Burden) is a net resistance of 1 Ω and carries a turbulent current of 1 A at a power factor of 0.5. What will be its ratio error?

**3.** For a C.T. the transformation ratio is given by which of the following relation?

- R = Is/Ip
- R = Ip/Is
- R = 1/Is
- R = 1/Ip

**4.** The ratio of transformation in the case of potential transformers

- Increases with increases in power factor of secondary burden
- Remains constant irrespective of the power of secondary burden
- Decreases with increases in power factor of Secondary burden
- None of the above

**5. **For a P.T. the transformation ratio is given by which of the following relation?

- R = Vs/Vp
- R = Vp/Vs
- R = 1/Vs
- R = 1/Vp

**6.** In a current transformer, the ratio of rated primary current to rated secondary current is called:

- nominal ratio
- ratio error
- phase angle error
- actual transformation ratio

**7.** Nominal ratio of an instrument transformer is defined as the __________

- Reciprocal of the rated primary value
- Ratio of rated secondary value to primary value
- Reciprocal of the rated secondary value
- Ratio of rated primary value to secondary value

**8.** A 500 A/5A, 50 Hz current transformer has a bar primary. The secondary burden is a pure resistance of 1 Ω and it draws a current if 5 A If the magnetic core requires 250 AT for magnetization the percentage ratio error is

**9.** For a C.T. the nominal ratio is given by which of the following relation?

- K
_{n}= V_{s}(rated)/V_{p}(rated) - K
_{n}= V_{p}(rated)/V_{n}(rated) - K
_{n}= 1/V_{p}(rated) - K
_{n}= 1/V_{s}(rated)

**10.** Instrument transformers are known to introduce magnitude and phase errors in measurements. These are primarily due to

- Improper connections on the primary side
- Measurement errors inherent in the meter connected to the transfer secondary
- Open and short circuit parameters of the instrument transformers
- None

**11.** Ratio correction factor of instrument transformer is defined as _________

- Reciprocal of nominal ratio
- Ratio of nominal ratio to transformation ratio
- Ratio of transformation ratio to nominal ratio
- Reciprocal of transformation ratio

**12.** The primary winding exacting current of a current transformer with a bar primary, nominal ratio 100/1, operating on an external burden of 1.6 Ω non inductive, the secondary winding resistance being 0.2 Ω, is 1.9 A, lagging 40.6° to the secondary voltage reversed there being 100 secondary turns. Voltage reversed there being 100 secondary turns with 1 A flowing in the secondary winding. Calculate actual ratio

- 72.37
- 101.44
- 127.34
- 93.42

**13.** For a current transformer the turns ratio is defined as the _________

- n = Np ⁄ Ns
- n = 1 ⁄ Np
- n = Ns
- n = Ns ⁄ Np

**14.** The magnetizing and loss component of exciting current of a current transformer rated 1000/5 A, are 15 A and 9 A respectively. The phase angle between secondary winding induced voltage and current is 40 degree. The phase angle error of the transformer is

- 4.56
- 3.27
- 2.38
- 7.24

**15.** For a potential transformer the turns ratio is defined as the _________

- n =
^{Np}⁄_{Ns} - n =
^{1}⁄_{Np} - n = N
_{s} - n =
^{Ns}⁄_{Np}

**16.** A 100/5 A, 50 Hz current transformer has a bar primary and rated secondary burden of 10 VA the secondary winding has 186 turn and leakage inductance of 0.96 mH. With purely resistive burden at rated full load, the magnetization MMF is 14 A and loss excitation 9 A. Find the phase angle error.

- 0.14°
- 0.10°
- 0.05°
- 0.28°