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PHY 104 PHY 104 Past Questions Objective Question
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Question

Calculate the minimum wavelength of an X-ray tube operating at 30 kV.
Options
A 0.7 × 10^-10 m
Correct Answer
B 0.3 × 10^-10 m
C 3.4 × 10^-11 m
D 0.9 × 10^-13 m
Correct Answer

Option A is the correct answer.

Detailed Explanation

The minimum wavelength corresponds to the maximum photon energy, where eV = hc/λ_min. λ_min = hc/(eV) = (6.626e-34 × 3e8) / (1.602e-19 × 30000) = 1.9878e-25 / 4.806e-15 = 4.136e-11 m = 0.4136 × 10^-10 m. None of the options match exactly. Let's recheck: hc = 1240 eV·nm. 30 kV = 30000 eV. λ_min = 1240/30000 nm = 0.0413 nm = 4.13e-11 m. This is closest to 0.3 × 10^-10 m (which is 3 × 10^-11 m).

Hint

Use λ_min = hc/(eV).

Question Info

Course: PHY 104
Topic: PHY 104 Past Questions
Type: Objective
Difficulty: Not specified
Question 786 of 947
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