Answer:
Speed of sound inside metal is ≅ 8200 
Explanation:
Given :
Length of metal bar 
m
From general velocity equation,
Where 
speed of sound in air = 343
For finding time from above equation,
sec
Since pulses are separated by 
sec
So we take time difference,
So speed of sound in metal is,
solution:
When an uncharged conducting object brought near to a charged insulating object there is a force on the conducting object to move the electrons within it to opposite sides of the conductor. That means there is a separation of charges in the conducting object in the presence of the charged insulating object near to it but the charge on the conducting object is neutral.
Thus, the conducting object is uncharged.
There is a force of attraction between the uncharged conducting object and the insulating object when it brought near to the insulating object.
Thus, there is a force on the conducting object.
The conductor remains uncharged and a force is exerted on it.
1. A. The SI unit for current is the ampere.
2. C. The unit for resistance = ohm.
3. B. EMF is measured in volts.
4. B. Electric current is the flow of charged particles, i.e. electrons.
5. B or C. All other answers are metals.
6. C. The dimensions of a material don't affect its resistance.
7. D. Ohm's law: current = voltage / resistance, 12/4 = 3.
8. B. Batteries transform chemical energy into electrical energy.
9. A. Metals are generally good conductors.
