Answer:
Lithium and Sodium
Explanation:
Lithium and Sodium is in the same group 1A
-- Sound energy. That's how you hear it explode.
-- Light energy. That's how you see it in the sky.
-- Heat energy. That's why you get burned if sparks fall on you.
-- Potential energy, as all the pieces fall to the ground.
These were all stored in it as chemical energy before it exploded.
Answer: temperature of the hot reservoir is 303.52K
Explanation:
Th=temperagture of hot reservoir
Tc=temperature of cold reservoir 263K
Eff=efficiency of the refrigerator
Cop=coefficient of performance
7
Eff=1/cop
Eff=1/7
Eff=0.142
Eff=1-263/th
0.142-1=-263/th
-0.858=-263/th
Th=303.52K
Answer:
Option (d) is correct.
Explanation:
Work done is given by :
W = Fd, where F is force and d is displacement
Unit of work done :
The SI unit of force is Newton (N) and that of displacement is meter (m). So, the unit of work done is N-m. It is call Joule. It means that the unit of work done is Joule.
Power is given by rate at which the work is done. It is given by :
P = W/t, W is work done and t is time
Unit of power:
Unit of work is Joule (J) and that of time is second (s). It means that the unit of power is Watt and it is equal to Joule/second
Hence, the correct option is (d) "The unit for work is a joule. The unit for power is a watt, which is a joule per second".
Answer:
B) Electrons and protons
Explanation:
Each proton has a positive charge, and each electron has a negative charge. If the atom is electrically neutral, there must be the same number of electrons and protons.
A) and C) are wrong. Neutrons have no charge, so they can't counteract that of the protons or the electrons.
D) is wrong. The atomic number is the number of protons, and the mass number is the number of protons plus neutrons. The neutrons can't counteract the charge of the protons,
