MCQ Detailed View

A photocell, also known as a photoelectric cell, is a device that converts light energy into electrical energy. This process is based on the photoelectric effect, discovered by Albert Einstein, which explains how photons of light can liberate electrons from a material, typically a metal surface.

When light falls on the surface of a photocell, the photons transfer their energy to electrons in the metal. If the energy of the photons is greater than the work function of the metal, the electrons are ejected from the surface. These free electrons then move through an external circuit, producing an electric current. This is how light energy is effectively converted into electrical energy.

Other energy forms listed in the options behave differently:

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  Potential energy is energy stored due to position or configuration.

  
  


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  Chemical energy is energy stored in chemical bonds, as in batteries or fuel.

  
  


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  Heat energy is energy associated with temperature increase.

  
  

Photocells are widely used in solar panels, automatic street lights, light meters, and safety devices. They are a key example of renewable energy technology, demonstrating how natural resources like sunlight can be harnessed for practical electricity generation.

Understanding the working of a photocell teaches students about energy transformation, photons, electron movement, and practical applications of physics in daily life. It also emphasizes the importance of solar energy and sustainable technologies.

This question falls under Physics, particularly electromagnetism, energy conversion, and modern physics. Knowledge of how light energy is converted to electrical energy is fundamental for students studying physics and technology.