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A beam of cathode rays is subjected to crossed Electric(E) and Magnetic fields(B). The fields are adjusted such that the beam is not deflected. The specific charge of the cathode rays is given by: (Where V is the potential difference between cathode and anode).
Options
(a) B² / 2VE²
(b) 2VB² / E²
(c) 2VE² / B²
(d) E² / 2VB²
Correct Answer:
E² / 2VB²
Explanation:
For no deflection of beam, eE = evB ⇒ v = E/B
Also, 1/2 mv² = eV ⇒ v = E/B
e/m = v² / 2V = E² / 2VB²
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Topics: Dual Nature of Matter and Radiation
(150)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- The fossil bone has a ¹⁴C:¹²C ratio, which is [1/16] of that in a living animal
- If force(F),length(L) and time(T) be considered fundamental units, then the units of mass
- The diameter of the eye ball of a normal eye is about 2.5 cm. The power of the eye
- A transformer having efficiency of 90% is working on 200 V and 3kW power supply
- A train is moving along a straight path with uniform acceleration
Topics: Dual Nature of Matter and Radiation (150)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
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