Which one of the following metals is used in the filaments of photo-electric cells that convert light energy into electric energy ?

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Q: 58 (NDA-I/2018)

Which one of the following metals is used in the filaments of photo-electric cells that convert light energy into electric energy ?

question_subject: 

Science

question_exam: 

NDA-I

stats: 

0,9,31,24,6,9,1

keywords: 

{'metals': [1, 2, 2, 7], 'filaments': [0, 0, 0, 1], 'electric cells': [0, 0, 0, 1], 'copper': [1, 0, 1, 1], 'light energy': [0, 0, 0, 2], 'aluminium': [1, 0, 3, 2], 'electric energy': [0, 0, 0, 4], 'tungsten': [0, 0, 0, 2], 'rubidium': [0, 0, 0, 4]}

The correct answer is option 3: Rubidium.

In photoelectric cells, light energy is converted into electric energy. The filaments in these cells play a crucial role in this process. The filaments are made of a metal that has the ability to emit electrons when exposed to light.

Option 1: Tungsten is a commonly used metal in incandescent light bulbs due to its high melting point and durability. However, it is not typically used in the filaments of photoelectric cells.

Option 2: Copper is a good conductor of electricity but does not possess the property of emitting electrons when exposed to light. It is therefore not suitable for use in photoelectric cell filaments.

Option 4: Aluminium is also a good conductor of electricity but does not have the necessary characteristics for converting light energy into electric energy. It is not used in the filaments of photoelectric cells.

Option 3: Rubidium is the correct answer. Rubidium has the ability to emit electrons when exposed to light, making it an ideal metal for use in the filaments of photoelectric cells.