In the described transformer example, the ratio of primary to secondary voltage is approximately:

In the described transformer example, the ratio of primary to secondary voltage is approximately:

• A. 1:2
• B. 8.67:1
• C. 4.16:0.48
• D. 1:8.67

Answer: (B)

The key idea is that a transformer’s voltage ratio reflects its turns ratio: Vp/Vs ≈ Np/Ns. If the described transformer goes from about 4.16 kV on the primary to about 0.48 kV on the secondary, then Vp/Vs ≈ 4.16/0.48 ≈ 8.67. Expressed as a primary-to-secondary ratio, that’s roughly 8.67:1. This is the clearest, standard way to communicate how much larger the primary voltage is compared with the secondary, and it matches the given voltages without carrying unit labels in the ratio itself. The other options either imply a different orientation (e.g., a step-down vs. step-up mismatch), or present the same ratio in a non-standard form (like 4.16:0.48, which ties the ratio to the specific voltages rather than stating the normalized ratio).

The key idea is that a transformer’s voltage ratio reflects its turns ratio: Vp/Vs ≈ Np/Ns. If the described transformer goes from about 4.16 kV on the primary to about 0.48 kV on the secondary, then Vp/Vs ≈ 4.16/0.48 ≈ 8.67. Expressed as a primary-to-secondary ratio, that’s roughly 8.67:1. This is the clearest, standard way to communicate how much larger the primary voltage is compared with the secondary, and it matches the given voltages without carrying unit labels in the ratio itself. The other options either imply a different orientation (e.g., a step-down vs. step-up mismatch), or present the same ratio in a non-standard form (like 4.16:0.48, which ties the ratio to the specific voltages rather than stating the normalized ratio).