he speed of the student relative to shore is
v_ up = v- vs
v _down = v+ vs
The time required to travel distance d upstream
is
t_up = d/ v_up = d/ v- vs
(2)
The time required to swim the same distance d downstream is
t_down = d/ v_down = d/ v+ vs
Velocity is a vector quantity and depends on both speed and direction.
In 100m you only travel straight in one direction.
But in 400m you have to turn corners and then go back the way you came, and then turn another corner, you're changing direction - hence changing velocity, even if the speed is the same.
Answer:a
Explanation:
Given
Potential difference 
Power of bulb A 
Power of bulb B 
If voltage is same for both the bulbs then Power is given by




similarly



so current in bulb A is smaller than B
Thus the 60 W bulb has a greater resistance.
Thus option (a) is correct
Answer:
0.000109375 m
Explanation:
d = Distance between grating = 0.5 mm
m = Order

Minima relation

For fourth order minima

For second maxima

From the two equations we get

The wavelength is 0.000109375 m