Answer:
.................... protons :)
Answer:
0.0786
Explanation:
zero after the decimal place is not a significant figure since it comes before the real integer "7".
"5 " in ten thousandth place is rounded off to "6" because the next digit is also another "5",
so we get the three sfg 0.0786
Answer:
Here ball and rod will repel each other as they are of similar charges
Explanation:
As we know that the two charges attract or repel each other by electrostatic force
This force is given as

so we know if two charges are similar in nature then they will repel each other and if the two charges are opposite in nature then they will attract each other
So here when rod touch the ball then it transfer its charge to the ball and due to similar charges in ball and rod they both repel each other
Answer:
150000000000 m
0.0000005 seconds
33.33 ns
Explanation:
Speed of electromagnetic waves through vacuum = 
Echo time = 1000 seconds
Echo time is the time taken to reach the object and come back to the observer
Distance = Speed×Time

Venus is 150000000000 m away from Earth
Time = Distance / Speed

Echo time will be twice the time

The echo time will be 0.0000005 seconds
Difference in time = Difference in distance / Speed

The accuracy by which I will be able to measure the echo time is 33.33 ns
Answer:
Explanation:
I suppose it has to do with the way the diagram is drawn. The heat does not reflect which makes both A and B incorrect.
C would have nothing to do with either reflection or refraction.
That only leaves D which is the answer.