PH 202

Quiz # 01 (10 pts)

Name

Solution

 

 Rey Skywalker walks across a carpet and she finds that her left shoe has a total charge of

+7.4 x 10-14 C on it.  When she started the shoe was electrically neutral.  How many electrons were transferred between her shoe and the carpet and were they transferred from the carpet or to the carpet by her walking?

 

A.

 Transferred to the Carpet

C.

 Transferred from the Carpet

 

 

 

 

B.

 Transferred to the Carpet

D.

 Transferred from the Carpet

 

 

 

 

 

Since the charge is positive it is less electrons so they were transferred to the carpet. 

 

So Correct Answer is B.

 

 

A pair of charges is located as shown in the diagram on the left.  What is the magnitude and direction of the electric force exerted by charge (a) on charge (b)?

 

A.

C.

 

 

 

 

B.

D.

 

Since the charges are opposite, charge (a) pulls charge (b) up!

 

 

So Correct Answer is D.

 

 

 A -7.2 mC charge is located at the origin.  What is the magnitude and direction of the electric field at the point (b) located on x axis at x = 2.00 m?

 

A.

C.

 

 

 

 

B.

D.

 

Since test charge for determining direction is positive.  A negative charge attracts, so the electric field at point (b) would point towards the charge and therefore point in the  direction. 

 

Therefore, the answer is B!

 

For a point charge, the electric field is found by

 

 

Negative sign makes it the which in this situation becomes the  direction.  Now we can ignore – sign of charge.

 

 

 

A on object has a net charge of +67.0 C on it.  It is placed in an electric field and as a result it experiences a force of .  What is the magnitude and direction of the Electric field the object was placed in?

 

A.

C.

 

 

 

 

B.

D.

 

Since the object is positively charged, feeling a force to the left, means the field also points to the left.

 

So

 

So Correct Answer is C.

 

 

An object has a mass of 1.30 kg.  It is placed into an electric field .  This results in an acceleration of .  What is the charge on the object, include the sign.

 

A.

B.

C.

D.

 

Since the acceleration is opposite to the field, the charge must be negative.

 

Solve for q

 

 

Right Answer is A!

 

 

 

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This page last updated on August 28, 2020