d. mass per unit volume
when an electron jumps from one energy level to another, the energy of atom gets changed.
if a photon gets absorbed, the electron will move to higher energy levels and then fall back to the lower energy levels. then each time a photon will be absorbed whose energy is given by difference between the initial and final energy levels i.e
in balmer series, the transition is from higher energy levels to n = 2.
so, the necessary condition for balmer series is that the electron should be at first excited state or n = 2 level as shown in figure.
answer: the entangled players would move with a speed of 0.2 m/s in the direction direction of the motion of second soccer player.
from law of conservation of momentum,
initial momentum of the closed system = final momentum of the closed system
since, no external force is acting on the players, total momentum would be conserved.
where, m₁ is the mass of one soccer player = 40 kg
u₁ is its initial velocity before collision = 4 m/s
m₂ is the mass of the other soccer player = 60 kg
u₂ is the initial velocity before collision = - 3 m/s (∵opposite direction)
after collision, the two players get entangled and hence move with the same final velocity v.
40 kg × 4 m/s - 60 kg × 3 m/s = (40 kg + 60 kg ) v
160 kg m/s - 180 kg m/s = 100 kg v
v = -0.2 m/s
hence, the entangled players would move with a speed of 0.2 m/s in the direction direction of the motion of second soccer player.
here we can use the concept of mechanical energy conservation
now we know that
m = 60 kg
as its going down
now from above equation we will have
so his speed will be 14.57 m/s