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Saturday, 31 October

JEE Main 2024 · PhysicsNumerical answerNumerical valueMediumMulti-step

JEE Main 8 April 2024, Shift 2, Physics Q60

Question 60 of 90 in this shift, Physics question 30 of 30, Section B.

A potential divider circuit is connected with a dc source of 20 V, a light emitting diode of glow in voltage 1.8 V and a zener diode of breakdown voltage of 3.2 V. The length (PR) of the resistive wire is 20 cm. The minimum length of PQ to just glow the LED is ____________ cm.

The figure, in words

Potential divider: 20 V dc source across a vertical resistive wire PR (P at top, R at bottom) with a sliding contact Q; from P an LED in series with a zener diode connects to the slider Q.

Official answer

5

NTA final key.

Same idea in other shifts

Asked 15× in all
  1. 2 Apr 2025, Shift 1 · Q45A zener diode with 5 V zener voltage is used to regulate an unregulated dc voltage input of 25 V. For a 400 Ω400\ \Omega resistor connected…MediumSingle correct
  2. 7 Apr 2025, Shift 1 · Q45In the following circuit, the reading of the ammeter will be (Take Zener breakdown voltage = 4 V)MediumDiagram basedHas a figure
  3. 29 Jan 2024, Shift 1 · Q48In the given circuit, the breakdown voltage of the Zener diode is 3.0 V. What is the value of IzI_z?MediumDiagram basedHas a figure
  4. 30 Jan 2024, Shift 1 · Q48A Zener diode of breakdown voltage 10 V is used as a voltage regulator as shown in the figure. The current through the Zener diode is :MediumDiagram basedHas a figure
  5. 26 Jul 2022, Shift 1 · Q60In the circuit shown below, maximum zener diode current will be __________ mA.MediumNumerical valueHas a figure
  6. 29 Jul 2022, Shift 2 · Q58A 8 V Zener diode along with a series resistance R is connected across a 20 V supply (as shown in the figure). If the maximum Zener…MediumNumerical valueHas a figure
  7. 24 Jun 2022, Shift 2 · Q55In the given circuit, the value of current ILI_L will be ________ mA. (When RLR_L = 1kΩ\Omega)MediumNumerical valueHas a figure
  8. 28 Jun 2022, Shift 2 · Q52A zener of breakdown voltage VZ_Z=8 V and maximum zener current, IZM_{ZM}=10 mA is subjected to an input voltage Vi_i=10 V with series…MediumNumerical valueHas a figure

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.