The correct answer of this question is : A) Change alternating current into direct current.
EXPLANATION :
As per the question, we are given vacuum tube. Vacuum tube can be of various types. Normally it contains two electrodes called cathode and anode which are enclosed in an evacuated glass chamber . There are also other types of vacuum tubes which contain extra electrodes like control grid .
The vacuum tube can be used as a rectifier. It means that it can be used as an electronic device which will convert alternating current into direct current. It may be a half wave rectifier or a full wave rectifier. Actually the direct current obtained during the rectification of alternating current is pulsating in nature.
Hence, the correct answer is that a vacuum tube can be used to change alternating current into direct current.
Hi there! When a chemical Reaction happens, the tell tale signs are as listed:
~The chemical produces bubbles
~ The Chemical emits an odor
~ The liquid forms a solid(Precipitate)
~ There is a change of color
~ And last but not least a change in temperature!
Hope this can help! Good luck!
Answer:

Explanation:
given,
F = 14.1 i + 0 j + 5.1 k
displacement = 6 m
Assuming block is moving in x- direction
we know,
dW = F dx


![W = F[x]_0^6](https://tex.z-dn.net/?f=W%20%3D%20F%5Bx%5D_0%5E6)


hence, work done by the force is equal to 
Current = (voltage) / (resistance)
= (35 volts) / (1,400 ohms)
= 25 milliamperes