Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
KCET2010PhysicsCurrent Electricity

B ₁, ~B ₂ and B ₃ are the three identical bulbs connected to a battery of steady emf with key K closed. What happens to the brightness of the bulbs B₁ and B₂ when the key is opened?

Options

  1. ABrightness of the bulb B ₁ increases and that of B ₂ decreases
  2. BBrightness of the bulbs B ₁ and B ₂ increase
  3. CBrightness of the bulb B ₁ decreases and B ₂ increases
  4. DBrightness of the bulbs B ₁ and B ₂ decrease

Correct answer

C. Brightness of the bulb B ₁ decreases and B ₂ increases

Step-by-step solution

When key K is opened, bulb B ₂ will not draw any current from the source, so that terminal voltage of source increases. Hence, power consumed by bulb increases, so light of the bulb becomes more. The brightness of bulb B ₁ decreases.

Practice Current Electricity on Quantrex Academy →

More from Current Electricity

The voltage – current graph for a metal wire of uniform area of cross section at two different temp T and T' is shown. Then choose the correct statement: 2026Find the current through the 40 resistor in the given circuit having a diode, three resistors and two cells. 2026A series combination of 'n' cells of emf 'E' and internal resistance 'r' each, are connected across the external resistance 'R'. If the internal resistance 'r' is negligibly small, 2026An electric coil is rated 400W, 200V. It is cut into two equal parts and connected in parallel to the same source of 200V. Calculate the percentage increase in energy produced per 2026A galvanometer of resistance 50 is having 30 divisions and a current sensitivity 10 mA/div. What should be the shunt resistance so that it can be converted into an ammeter of range 2026Current in a conductor is expressed as I = 8t^3 + 3t^2 + 1 , where current I is measured in amperes and time t is measured in seconds. What is the charge that flows through a cross 2026In the given circuit, an ideal voltmeter connected across 6 reads 5V. The internal resistance r of each cell is: 2026A wire of length 1m has a resistance of 20 at 0^ C. It is uniformly stretched so that its length increases by 21%. Assuming the volume of the wire remains constant, the percentage 2026 Full Current Electricity list All KCET PYQs