# Multiple Choice (1 Viewer)

1) b
2) d
3) a
4) a
5) d
6) c
7) a
8) d
9) b
10) c
11) b
12) a
13) d
14) b
15) a
16) d
17) b
18) c
19) c
20) b

#### someth1ng

##### Retired Nov '14
Q17 is a bit ambiguous but the best answer is D. If the change in torque was constant, then torque would continue to increase, resulting in the motor to speed up to infinity. The back emf in the motor will cause the torque to decrease to zero over time.

#### someth1ng

##### Retired Nov '14

1) b
2) d
3) a
4) a
5) d
6) c
7) a
8) d
9) b
10) c
11) b
12) a
13) d
14) b
15) a
16) d
17) d
18) c
19) c
20) b

Torque one is tricky! But, the most correct answer would have to be D as net current through the coil would be decreasing due to Back EMF
Q5 is a bit of a lame question but yeah, I agree with all answers here.

#### fionarykim

##### Member
how come 11 is B? X rays have the longest wavelength in the electromagnetic spectrum?
so how can the answer be that they have a short wavelength?

#### nerdasdasd

how come 11 is B? X rays have the longest wavelength in the electromagnetic spectrum?
so how can the answer be that they have a short wavelength?
Radio waves have a long wavelength(used to transmit voices over hundreds of km's), not gamma or x rays.

#### someth1ng

##### Retired Nov '14
Those didn't explain it at all...

For X-ray diffraction, you need the wavelength to be about the same as interatomic spacing.

And that's true for X-rays.

#### fionarykim

##### Member
ohhhh right yeahh ooops my bad
thanks guys!