A ray of light is incident on a medium with angle of incidence i and refracted into a second medium with angle of refreaction r. The graph of sin i vs sin r is shown in the figures. Then the velocity of light in the first medium is n times the velocity of light in the second medium. The value of n should be.
Equation of sound wave in air is given by . Find the speed of sound in air.
A physical quantity P is described by the relation
P= a^{1/2} b^{2} c^{3} d^{-4}
If the relative errors in the measurement of a, b, c and d respectively, are 2%, 1%, 3% and 5%,
then the relative error in P will be :
8%
12%
32%
25%
A standing wave is formed by the superposition of two waves travelling in opposite directions. The transverse displacement is given by
What is the speed of the travelling wave moving in the positive x direction ?
(x and t are in meter and second, respectively.)
160 m/s
90 m/s
180 m/s
120 m/s
In a meter bridge experiment resistance are connected as shown in the figure. Initially resistance P=4 and the neutral point N is at 60 cm from A. Now an unknown resistance R is connected in series to P and the new position of the neutral point is at 80 cm from A. The value of unknown resistance R is :
A 9 V battery with internal resistance of 0.5 is connected across an infinite network as shown in the figure. All ammeters A1, A2, A3 and voltmeter V are ideal.
Choose correct statement.
Reading of A_{1} is 2 A
Reading of A_{1} is 18 A
Reading of V is 9 V
Reading of V is 7 V
Wheatstone bridge is the most sensitive when all the four resistances are of the same order of magnitude.
In a balanced wheatstone bridge if the cell and the galvanometer are exchanged, the null point is disturbed.
A rheostat can be used as a potential divider.
Kirchhoff’s second law represents energy conservation.
As we learnt in
To find resistance of a given wire using metre bridge and hence determine the specific resistance -
For unknown resistance
x= Unknown resistance
R= Given resistance
- wherein
Calculation
= .........ohms
= Resistivity
X = Unknown resistance
D = Diametre
L = length of wire
There is no change in null point, if the cell and the galvanometer are exchanged in a balanced bridge.
So, option (2) is the answer
Balancing condition
Balancing condition
Option 1)
Wheatstone bridge is the most sensitive when all the four resistances are of the same order of magnitude.
Incorrect
Option 2)
In a balanced wheatstone bridge if the cell and the galvanometer are exchanged, the null point is disturbed.
Correct
Option 3)
A rheostat can be used as a potential divider.
Incorrect
Option 4)
Kirchhoff’s second law represents energy conservation.
Incorrect
A magnetic needle of magnetic moment 6.7×10^{−2} Am^{2} and moment of inertia 7.5×10^{−6} kg m^{2} is performing simple harmonic oscillations in a magnetic field of 0.01 T. Time taken for 10 complete oscillations is :
6.65 s
8.89 s
6.98 s
8.76 s
A magnetic dipole in a constant magnetic field has :
maximum potential energy when the torque is maximum.
zero potential energy when the torque is minimum.
zero potential energy when the torque is maximum.
minimum potential energy when the torque is maximum.
A negative test charge is moving near a long straight wire carrying a current. The force acting on the test charge is parallel to the direction of the current. The motion of the charge is :
away from the wire
towards the wire
parallel to the wire along the current
parallel to the wire opposite to the current
A uniform magnetic field B of 0.3 T is along the positive Z-direction. A rectangular loop (abcd) of sides 10 cm×5 cm carries a current I of 12 A. Out of the following different orientations which one corresponds to stable equilibrium ?
In a certain region static electric and magnetic fields exist. The magnetic field is given by
If a test charge moving with a velocity experiences no force in that region, then the electric field in the region, in SI units, is :