Sound moves with higher velocity if:
pressure of the medium is decreased
temperature of the medium is increased
the humidity of the medium is increased
both B and C above
Which one of the following is the correct angle between the incident and reflected rays when a ray of light incident normally on a plane mirror?
180°
90°
45°
0°
D.
0°
When a ray of light incident normally on a plane mirror. The ray will revert back to its path as a result both angle of incidence & reflection will be zero.
The magnetism of a bar magnet can be destroyed if it is:
Select the correct answer using the code given below:
1 and 3 only
2 only
2 and 3 only
1,2 and 3
The capacity of a parallel plate condenser can be doubled by:
Select the correct answer using the code given below:
1 and 4
1 and 3
3 only
2 and 3
If two conducting spheres are separately charged and then brought in contact:
the total energy ofthe two spheres is conserved
the total charge on the spheres is conserved
both the total energy and charge are conserved
the final potential is always the mean of the original potential of the two spheres
Two pieces of metallic wire having an equal length and equal volume placed in the air have different resistances. The two wires must:
have different cross-sections
have different temperatures
be of different materials
be of same density
If a heater coil is cut into two equal parts and only one part is used in the heater, the heat generated will be :
doubled
four times
one-fourth
halved
The direction of the magnetic field at a point due to an infinitely long wire carrying current is:
parallel to the current
antiparallel to the current
along the perpendicular drawn from a point on the wire
perpendicular to the plane containing the conductor and the point
A hollow metal ball-carrying an electric charge produces no electric field at points:
outside the sphere
on its surface
inside the sphere
only at the centre