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PHY 104 PHY 104 Past Questions Objective Question
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Question

Calculate the speed of the electron as it hits the target in an X-ray tube operating at 40 kV when a current of 3.0 mA passes through.
Options
A 3.0 × 10^8 m/s
B 1.3 × 10^8 m/s
C 0.75 × 10^8 m/s
D 1.2 × 10^8 m/s
Correct Answer
Correct Answer

Option D is the correct answer.

Detailed Explanation

The speed is determined by the voltage: ½mv² = eV. V = 40 kV = 40,000 V. v = √(2eV/m) = √(2 × 1.602e-19 × 40000 / 9.11e-31) = √(1.2816e-14 / 9.11e-31) = √(1.4068e16) = 1.186e8 m/s ≈ 1.2 × 10^8 m/s.

Hint

The kinetic energy is eV.

Question Info

Course: PHY 104
Topic: PHY 104 Past Questions
Type: Objective
Difficulty: Not specified
Question 810 of 947
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