1 ) In
rare medium [ e.g. air ] , the velocity of light is ………..
a) Greater b)
Smaller c) normal
d) none of these
The
correct option is : - a )
Greater .
2 ) In denser medium [ e.g. glass ] , the velocity of light is
…….....
a) Greater
b) Smaller
c) No change in velocity of light
d) none of these
The correct option is : - b ) Smaller .
Because speed of light depends on the refractive index of the medium . And the
refractive index is the opposition to
the flow of light . So which medium
have higher refractive index , so its speed will be greater . { More refractive index , lesser will be
its speed } .
The refractive index of any of the denser
medium is greater than 1 and vacuum has almost zero refractive index . So that
speed of light is maximum in air than denser medium.
And we have formula for refractive index : -
As we know
that the speed of light in vacuum is approximately ( 3 x 10 ^ 8 m/s) . The reason behind this large value is that vacuum has no density , while glass are
denser than vacuum. And vacuum has nil refractive index .
3 ) Angle btw linear acceleration and angular
acceleration is ………………. ,
A ) 0 degree , B
) 90 degree ,
C ) 180 degree , D
) None of these ,
Correct
Answer : - B ) 90 degree ,
Because in a
nonuniform circular motion, we have two tyes of acceleration ; linear and
angular acceleration . Angular acceleration is a axial vector which is perpendicular
to the plane of motion and linear acceleration is in the plane of a motion . Hence, the linear and angular
acceleration have angle of 90 degree .
One more concept that the angular acceleration and linear
acceleration are directly proportional to each other . So greater
the value of angular
acceleration , the larger will be the linear acceleration and vice versa .
Now go to online quiz section and check your preparation by this link : -
