Question Detail

PHY 102 Test Compilation PHY 102 20 Objective Question
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Question

How many excess electrons must be placed on two spheres 3 cm apart to produce a force of 0.0256 N? (e = 1.6x10-19 C, k = 9x109)
Options
A 5.00 x 100 electrons
B 1.98 x 103 electrons
C 3.16 x 1011 electrons
Correct Answer
D 3.16 x 10-11 electrons
Correct Answer

Option C is the correct answer.

Detailed Explanation

First find q: F = kq2/r2 => q = sqrt(F r2/k) = sqrt[(0.0256)(0.03)2/9x109] = sqrt[2.304x10-5/9x109] = sqrt(2.56x10-15) = 5.06x10-8 C. Number of electrons n = q/e = 5.06x10-8/1.6x10-19 = 3.16x1011 electrons.

Hint

First find q: F = kq2/r2 => q = sqrt(F r2/k) = sqrt[(0.0256)(0.03)2/9x109] = sqrt[2.304x10-5/9x109] = sqrt(2.56x10-15) = 5.06x10-8 C.

Question Info

Course: PHY 102
Topic: Test Compilation PHY 102 20
Type: Objective
Difficulty: Not specified
Question 1233 of 1819
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