I know we are not supposed to ask more than one question, but I need some help o
ID: 1956893 • Letter: I
Question
I know we are not supposed to ask more than one question, but I need some help on a few multiple choice problems. This is not homework, just a practice test that I was working on. If you could provide the answer and a quick explaination, I would really appreciate it. Thank you!
1) Suppose two resistors R1 and R2 are hooked up in series. These two have an equivalent resistance:
a) larger than either R1 or R2
b) smaller than either R1 or R2
c) between that of R1 and R2
d) equal to R1
e) equal to R2
d) that depends on the voltage across them
2) A 1 C charge and a 2 C charge are separated by 1 m. If their separation is increased to 2 m, the strength of the electric force of one charge on the other:
a) remains the same
b) decreases by a factor of 2
c) decreases by a factor of 2
d) decreases by a factor of 4
e) decreases by a factor of 2
f) increases by a factor of 4
3) In which of the circuits below is the total current I out of the battery the largest? The battery in each circuit has the same EMF.
a) 1 b) 2 c) 3 d) 4 e) 1 & 4 f) Current is the same in all of them.
4) If you move a -1C charge from the origin where the electric potential is 10V to the point x=3 where the potential is 10V, the electric potential energy of the electron:
a) remains the same
b) decreases by 30J
c) decreases by 30 x 10-6 J
d) increases by 30 x 10-6 J
e) increases by 30 J
f) increases by 30 x 10-6 J
Explanation / Answer
1. In series the equivalent Resistance is the sum of all the Resistances.
Req = R1 + R2
So option A is correct one as Req is larger than either of R1 and R2
2.
Electric Field is given by E= KQ/R2
Initial Seperation = 1m
put R=1 m, we get
E = KQ
Final Seperation = 2m
R' = 2m
We get, E' =KQ/4 = E/4
Therefore Electric field decreases by a factor of 4
Option D is correct
3. Current I is largest in Circuit which has the least Equivalent Resistance.
Req of Circuit 1 is the least with Req = R/2
Hence current in Circuit 1 is the highest
Therefore Option A is correct
4. The electric potential Energy is defined as the Potential at that point multiplied by the Charge.
The Potential Energy at both the location remains the same.
Hence option- A is correct