The self-inductance of a long solenoid carrying current is independent of
its length
the current
its cross-sectional area
magnetic permeability of the core
The rms value of AC which when passed through a resistor produces heat, which is twice that produced by a steady current of 1.414 A in the same resistor is
2 A
3.46 A
2.818 A
1.732 A
In a series LCR AC circuit, the current is maximum when the impedance is equal to
the reactance
the resistance
zero
twice the reactance
If the directions of electric and magnetic field vectors of a plane electromagnetic wave are along positive y- direction and positive z-direction respectively, then the direction of propagation of the wave is along
positive z-direction
negative z-direction
negative y-direction
positive x-direction
When an object is viewed with a light of wavelength 6000 under a microscope, its resolving power is 104. The resolving power of the microscope when the same object is viewed with a light of wavelength 4000 , is
104
2 × 104
1.5 × 104
3 × 104
Secondary rainbow in the atmosphere is
the result of polarization and dispersion of light
brighter than the primary rainbow
formed due to two reflections in the rain drop
formed with red colour on the top
For a diffraction from a single slit, the intensity of the central point is
infinite
finite and same magnitude as the surrounding maxima
finite but much larger than the surrounding maxima
finite and substantially smaller than the surrounding maxima
If the radius of curvature of the curved surface of a plano -convex lens is 50 cm, its focal length is (µ =1.5)
0.5 m
0.75 m
1 m
0.25 m
C.
1 m
From lens formula,
The magnification of an image by a convex lens is positive only when the object is placed
at its focus F
between F and 2F
at 2F
between F and optical centre