Question Detail

PHY 102 Test Compilation PHY 102 20 Objective Question
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Question

How many excess electrons must be placed on each of two small spheres spaced 3 cm apart, if the repulsive force between the spheres is to be 10-18 N? (e=1.6x10-19 C, k=9x109)
Options
A 5.00 x 100 electrons
B 1.98 x 103 electrons
Correct Answer
C 3.16 x 1016 electrons
D 3.16 x 10-16 electrons
Correct Answer

Option B is the correct answer.

Detailed Explanation

q = sqrt(F r2/k) = sqrt[(10-18)(0.03)2/9x109] = sqrt[9x10-22/9x109] = sqrt(1x10-31) = 3.16x10-16 C. n = q/e = 3.16x10-16/1.6x10-19 = 1.98x103 electrons.

Hint

q = sqrt(F r2/k) = sqrt[(10-18)(0.03)2/9x109] = sqrt[9x10-22/9x109] = sqrt(1x10-31) = 3.16x10-16 C.

Question Info

Course: PHY 102
Topic: Test Compilation PHY 102 20
Type: Objective
Difficulty: Not specified
Question 1237 of 1819
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