C. Combustion reaction.
These reaction are exothermic.
The reactions are:
2Mg + O2 -----> 2MgO
3Mg + N2 ------> Mg3N2
Answer:
Unknown
Explanation:
Because we cannot observe space beyond the edge of the observable universe, it is unknown whether the size of the Universe in its totality is finite or infinite.
Answer:
decibel gain is 10 db
Explanation:
given data
voltage v1 = 5 volts
voltage v2 = 15 volts
to find out
decibel gain
solution
we have given that 5 volt voltage that is increase to 15 volts
so
we know here decibel gain formula that is
decibel gain = 20 log(v2/v1) ....................1
put here value of v1 and v2 in equation 1
decibel gain = 20 log(15/5)
decibel gain = 20 log3
decibel gain = 20 × 0.4771
decibel gain = 9.54 db = approx 10 db
so decibel gain is 10 db
This type of energy is called non mechanical energy so the answer is C
