Q14.A velocity selector consists of electric field 𝐸= 𝐸 ^k and magnetic field 𝐵= 𝐵 ^j with 𝐵= 12 mT. The value 𝐸 required for an electron of energy 728eV moving along the positive x-axis to pass undeflected is (Given, mass of electron = 9 . 1 × 10-31 kg) (1) 192 kV m-1 (2) 192 mV m-1 (3) 9600 kV m-1 (4) 16 kV m-1
What This Question Tests
This question involves calculating the electron's velocity from its kinetic energy and then applying the condition for undeflected motion in crossed electric and magnetic fields (Lorentz force).
Concepts Tested
Formulas Used
F_E = qE
F_B = q(v x B)
K = 1/2 mv^2
📚 NCERT Sections This Tests
4.11 — In A Chamber, A Uniform Magnetic Field Of 6.5 G (1 G = 10–4 T) Is
Physics Class 11 · Chapter 4
4.11 In a chamber, a uniform magnetic field of 6.5 G (1 G = 10–4 T) is maintained. An electron is shot into the field with a speed of 4.8 × 106 m s–1 normal to the field. Explain why the path of the electron is a circle. Determine the radius of the circular orbit. (e = 1.5 × 10–19 C, me = 9.1×10–31 kg)
4.4 — A Horizontal Overhead Power Line Carries A Current Of 90 A In East To
Physics Class 11 · Chapter 4
4.4 A horizontal overhead power line carries a current of 90 A in east to west direction. What is the magnitude and direction of the magnetic field due to the current 1.5 m below the line?
11.3 — The Photoelectric Cut-Off Voltage In A Certain Experiment Is 1.5 V.
Physics Class 12 · Chapter 11
11.3 The photoelectric cut-off voltage in a certain experiment is 1.5 V. What is the maximum kinetic energy of photoelectrons emitted?
📋 Question Details
- Chapter
- Magnetic Effects of Current
- Topic
- Velocity Selector
- Year
- 2022
- Shift
- 26 Jul Shift 2
- Q Number
- Q14
- Type
- MCQ
- NCERT Ref
- Class 12 Physics Ch 4: Moving Charges and Magnetism
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