<span>Answer: A) They are isotopes of nitrogen and they contain the same number of protons and electrons but each contains a different number of neutrons - 7 and 8 respectively.
Isotopes are atoms of a chemical element whose nucleus has the same atomic number, Z, but different atomic mass, A. The atomic number corresponds to the number of protons in the atom, therefore the isotopes of an element contain the same number of protons and electrons (atoms have to be neutral particles). The difference in atomic masses arises from the difference in the number of neutrons in the atomic nucleus.
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R = ρ L/A. R= resistance, ρ= resistivity, L= length of the conductor. A = area of the conductor. Resistance is directly proportional to the length of the conductor. So if length of the conductor is decreased, resistance will also decrease. Hence A is the correct option
Answer:
a) 30 degree
Explanation:
As we know that time of flight of the projectile depends on the the vertical component of the velocity always
It is given as

now we know that

so we will have

since we know that two projectiles are projected at same speed but different angles
so smaller the angle will take smaller time
so it would be 30 degree projectile which will take smaller time