Question

Flash light equipped with a new set of batteries, produces bright white light. As the batteries wear out,

• A. the light intensity gets reduced with no change in its colour
• B. light colour changes first to yellow and then red with no change in intensity
• C. it stops working suddenly while giving white light
• D. colour changes to red and also intensity gets reduced

Answer 1

Answer: (D)

colour changes to red and also intensity gets reduced

Answer 2

As batteries wear out, temperature of filament of flash light attains lesser value, therefore intensity of radiation reduces. Also dominating wavelength $\left(\lambda_{ m }\right)$ in spectrum, which is the red colour, increases.