Transformers Quiz 1

Question 1

Mehta sir teaches physics to high school kids. One day a student asked a problem on transformers in which the number of turns in primary coil are $$1200$$ and in secondary coil is $$400$$ respectively. Now the current flowing through the primary coil is $$12	ext{ }A$$ then the current flows through the secondary coil is $$I$$ and this value is calculated by Mehta sir as $$	ext{6 }A$$. The percentage error in the calculation of Mehta sir is-

Accepted Answer

$$50	ext{ }%$$

Answer

$$40	ext{ }%$$

Answer

$$60	ext{ }%$$

Answer

$$100	ext{ }%$$

Question 2

If a $$300	ext{ }kVA$$ transformer is constructed by Ram in which he added a resistance of $$1.2$$ ohms is to primary coil with $$10	ext{ }kV$$ voltage and of $$	ext{0}	ext{.6}$$ ohms in secondary coil with $$	ext{5 }kV$$ voltage. The construction of a transformer is successful if copper loss is less than $$2000	ext{ }W$$. The ratio of current in coil two to coil one will be-

Accepted Answer

$$\dfrac{1}{2}$$

Answer

$$\dfrac{1}{3}$$

Answer

$$\dfrac{2}{3}$$

Answer

$$\dfrac{5}{4}$$

Question 3

A transformer having a voltage of $$30	ext{ }V$$ in primary coil and by step up the voltage the voltage in secondary coil becomes $$300	ext{ }V$$. The primary coil of the transformer has a number of turns $$30$$ and power of $$50	ext{ }W$$. The current flowing in secondary coil will be-

Accepted Answer

$$	ext{1}	ext{.66 }\,A$$

Answer

$$	ext{0}	ext{.5 }\,A$$

Answer

$$	ext{0}	ext{.85 }\,A$$

Answer

$$	ext{0}	ext{.08 }\,A$$

Question 4

A man bought an iron-cored transformer. The number of turns in the primary coil of the transformer are $$400$$ and in the secondary coil is $$10$$. A resistance of $$12	ext{ }\Omega $$ is connected in the secondary coil and voltage of $$360	ext{ }V$$ is connected in the primary coil. If the current flows in the primary coil is equal to current in a solenoid with $$550$$ number of turns per unit length then magnetic induction in a solenoid will be-<img  src="https://cmds-vedantu.s3.ap-southeast-1.amazonaws.com/prod/question-sets/91d648e3-c6df-4aa0-b81a-a45d45074bea1723620246544866268.png"/>

Accepted Answer

$$8.29	imes {{10}^{-1}}\,T$$

Answer

$$5.92	imes {{10}^{-5}}\,T$$

Answer

$$1.29	imes {{10}^{-5}}\,T$$

Answer

$$2.5	imes {{10}^{-4}}\,T$$

Question 5

A new transformer is to be constructed for a factory of required output power from the transformer of $$	ext{120 }kW$$. But the owner of the factory is aware of the condition that there will be some losses in the functioning of the transformer which will be equal to $$	ext{10 }kW$$. The efficiency of transformer will be equal to-

Accepted Answer

$$92.3\%$$

Answer

$$98.2\%$$

Answer

$$96.1\%$$

Answer

$$99.2\%$$