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Transformer Explained: How Electrical Transformers Work

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Question 1 of 50%

Transformers are indispensable components in modern electrical power systems, enabling efficient transmission of electricity over long distances and adapting voltage levels for various applications.

Test: Transformers

20 questions

Question 1: Transformers are indispensable components in modern electrical power systems, enabling efficient transmission of electricity over long distances and adapting voltage levels for various applications.

A. Yes

B. No

Explanation: The study materials state that 'Transformers are indispensable components in modern electrical power systems, enabling efficient transmission of electricity over long distances and adapting voltage levels for various applications, from household appliances to industrial machinery.'

Question 2: The power loss in transmission lines is calculated using the formula P_loss = I²R.

A. Yes

B. No

Explanation: The study materials state that the power loss in transmission lines is primarily due to the resistance of the wires and is given by the formula P_loss = I²R, where I is the current flowing through the line and R is the resistance of the line.

Question 3: Step-up transformers are primarily employed at power generation stations to decrease the voltage for local distribution.

A. Yes

B. No

Explanation: Step-up transformers are used at power generation stations to increase the voltage to very high levels for efficient long-distance transmission, not to decrease it for local distribution.

Question 4: In the provided worked example, the primary current (I₁) was calculated to be 5.0 A.

A. Yes

B. No

Explanation: The worked example calculates the primary current (I₁) using two methods. Both methods yield a primary current of 0.5 A, not 5.0 A. Specifically, I₁ = (20 V · 6.0 A) / 240 V = 0.5 A, or alternatively, I₁ = 6.0 A · (100 / 1200) = 0.5 A.

Question 5: In an ideal transformer, it is expected that the power delivered by the secondary winding is less than the power supplied to the primary winding.

A. Yes

B. No

Explanation: In an ideal transformer, there are no energy losses, meaning the electrical power supplied to the primary winding is equal to the electrical power delivered by the secondary winding (P₁ = P₂).