The sound was repeated because of the phenomenon of echo. The speed of sound in the metal is 800 m/s.
Echo results from the reflection of sound waves. The reason why a sound may be heard twice owes to the phenomenon of reflection which leads to echo.
To determine the speed of sound in the metal;
Length of metal = 1000 m
Time taken between the two sounds = 2.5 s
Using the formula;
V = 2d/t
V = 2(1000)/2.5
V = 800 m/s
Answer: electrical energy
Explanation:A battery is a device that is able to store electrical energy in the form of chemical energy, and convert that energy into electricity
Answer:
Wavelength, 
Explanation:
We have,
Velocity an electron is 
Mass of an electron is 
It is required to find the wavelength of electron. The De-Broglie wavelength of an electron is given by :

h is Planck's constant

So, the wavelength of an electron is
.
Answer:
V₁ = V = 120 V
Explanation:
Such a combination of capacitors in which;
1- Potential difference across each capacitor is the same
2- Total charge is distributed amongst the capacitors
; is called Parallel Combination.
Therefore, in this case, the potential difference across each capacitor will also be the same. Because the capacitors are connected in parallel here. So the voltage across 3 μF capacitor will be the same as the voltage across the 6 μF capacitor and they both will be equal to the total potential difference.
<u>V₁ = V = 120 V</u>