Question 1 Report
Which of the following reduce(s) the effect of the back e.m.f. generated in the primary coil of an induction coil? The capacitor in the circuit II. The make and break contact in the circuit III. The ratio of turns in the secondary to that in the primary
An induction coil is a device that converts high voltage, low current power to low voltage, high current power through electromagnetic induction. When an alternating current passes through the primary coil, a changing magnetic field is produced which induces an alternating current in the secondary coil. The back e.m.f. generated in the primary coil of an induction coil opposes the flow of current in the coil, causing a decrease in the current. This effect can be reduced by using a capacitor in the circuit, which stores the charge and releases it when the current drops. This maintains the flow of current and reduces the effect of the back e.m.f. Therefore, option I is correct. The make and break contact in the circuit also helps to reduce the effect of the back e.m.f. The contact repeatedly breaks the circuit, causing the current to stop flowing momentarily, which interrupts the magnetic field and reduces the back e.m.f. Therefore, option II is also correct. The ratio of turns in the secondary to that in the primary does not affect the back e.m.f. generated in the primary coil. It only affects the voltage induced in the secondary coil. Therefore, option III is incorrect. Hence, the correct answer is option C, I and II only.