Semiconductor diode I-V characteristics — NEET & JEE Questions

Question 1 · difficulty L1 · recall

A semiconductor diode conducts strongly when it is

• A. reverse biased below breakdown
• B. unbiased with no thermal carriers
• C. forward biased beyond its knee region
• D. connected with both terminals at the same potential only

Question 2 · difficulty L1 · understanding

In forward bias, a p-n diode is connected with p-side to

• A. the negative terminal
• B. ground only with no second connection
• C. another reverse-biased p-side
• D. the positive terminal of the supply

Question 3 · difficulty L2 · understanding

In reverse bias, the diode current before breakdown is typically

• A. small and nearly saturated
• B. larger than forward current by orders of magnitude
• C. exactly proportional to voltage like an ideal resistor
• D. zero because no minority carriers exist

Question 4 · difficulty L2 · application

The knee or cut-in voltage on a forward I-V curve marks

• A. the reverse-breakdown voltage
• B. the region where forward current begins increasing rapidly
• C. zero current at every voltage
• D. the maximum possible resistance

Question 5 · difficulty L2 · understanding

For an ordinary p-n junction diode, forward bias generally causes the current to

• A. increase rapidly after the knee or threshold region
• B. remain exactly zero at all voltages
• C. flow only as a tiny reverse saturation current
• D. decrease with increasing forward voltage

Question 6 · difficulty L3 · application

A silicon diode has a forward drop approximated as 0.7 V in a simple circuit. With a 5 V source and 430 Ω series resistor, current is about

• A. 1 mA
• B. 100 mA
• C. 10 mA
• D. 0.7 mA

Question 7 · difficulty L3 · application

A diode is reverse biased well below breakdown. Increasing reverse voltage modestly changes current

• A. by the same linear Ohmic amount as a resistor
• B. from positive to infinite instantly
• C. to a large majority-carrier current
• D. very little compared with forward-bias changes

Question 8 · difficulty L3 · application

A silicon diode is forward biased at a voltage well below its usual knee voltage. Its current is expected to be

• A. relatively small
• B. at maximum breakdown value
• C. a large reverse current
• D. independent of applied voltage

Question 9 · difficulty L3 · application

A diode is reverse biased below breakdown. Which current is normally observed?

• A. A small reverse saturation current
• B. A large forward conduction current
• C. Exactly the same current as in forward bias
• D. An infinite current

Question 10 · difficulty L4 · analysis

The dynamic resistance of a forward-biased diode at an operating point is approximated by

• A. ΔV/ΔI
• B. V/I only in every nonlinear case
• C. ΔI/ΔV
• D. VI