A semiconducting device is connected in a series circuit with a battery and a resistance. Current is found to pass through the circuit. If the polarity of the battery is reversed, the current drops to zero. The device may be

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Q: 77 (NDA-I/2014)
A semiconducting device is connected in a series circuit with a battery and a resistance. Current is found to pass through the circuit. If the polarity of the battery is reversed, the current drops to zero. The device may be

question_subject: 

Science

question_exam: 

NDA-I

stats: 

0,16,25,11,6,8,16

keywords: 

{'type semiconductor': [0, 0, 0, 2], 'circuit': [0, 0, 1, 3], 'intrinsic semiconductor': [0, 0, 0, 1], 'polarity': [0, 0, 0, 3], 'series circuit': [0, 0, 0, 1], 'device': [0, 0, 0, 1], 'battery': [0, 0, 1, 3], 'resistance': [0, 0, 1, 2]}

In this question, we are given a series circuit with a semiconducting device, a battery, and a resistance. The current passes through the circuit. However, when the polarity of the battery is reversed, the current drops to zero.

Option 1: p-type semiconductor

A p-type semiconductor has an excess of positively charged holes as majority carriers. It would not cause the current to drop to zero when the battery polarity is reversed. Therefore, option 1 is incorrect.

Option 2: n-type semiconductor

An n-type semiconductor has an excess of negatively charged electrons as majority carriers. It would not cause the current to drop to zero when the battery polarity is reversed. Therefore, option 2 is incorrect.

Option 3: an intrinsic semiconductor

An intrinsic semiconductor has an equal number of electrons and holes as majority carriers. It would not cause the current to drop to zero when the battery polarity is reversed. Therefore, option 3 is incorrect.

Option 4: p-n junction

A p-n junction is formed by connecting a p-type and an n-type semiconductor together. In a p-n junction, the current is allowed to flow only in one direction due to the formation of a depletion region. When the battery polarity is reversed, the depletion region widens