Q6 / 15 · NTA Abhyas (JEE Main) 2020 · Physics · Electromagnetic Waves
Cathode rays of velocity describe an approximate circular path of the radius in an electric field If the velocity of cathode rays are doubled. The value of electric field so that the rays describe the same circular path, will be
- A
- B
- Correct answerC
- D
Solution
Cathode rays are composed of electrons, when they move in electric field a force
...(i)
Acts on them, this provides the necessary centripetal force to the particles
...(ii)
From Eqs. (i) and (ii), we get
...(iii)
When velocity is doubled same circular path is followed, hence radius is same
...(iv)
Equating Eqs. (iii) and (iv), we get
V
...(i)
Acts on them, this provides the necessary centripetal force to the particles
...(ii)
From Eqs. (i) and (ii), we get
...(iii)
When velocity is doubled same circular path is followed, hence radius is same
...(iv)
Equating Eqs. (iii) and (iv), we get
V
Hence, the correct answer is option: 'C'.