Multiple Choice QuestionsA charge Q is uniformly distributed over a long rod AB of length L as shown in the figure. The electric potential at the point O lying at a distance L from the end A is
The diameter of the plano-convex lens is 6 cm and thickness at the centre is 3 mm. If speed of light in material of lens is 2 × 108 m/s, the focal length of the lens isÂ
15 cm
20 cm
30 cm
30 cm
A circular loop of radius 0.3 cm lies parallel to a much bigger circular loop of radius 20 cm. The centre of the small loop is on the axis of the bigger loop. The distance between their centres is 15 cm. If a current of 2.0 A flows through the smaller loop, then the flux linked with bigger loop isÂ
9.1 x 10-11 Wb
6 x 10-11 Wb
3.3Â x 10-11Â Wb
3.3Â x 10-11Â Wb
A diode detector is used to detect an amplitude modulated wave of 60% modulation by using a condenser of capacity 250 pico farad in parallel with a load resistance 100 kilo ohm. Find the maximum modulated frequency which could be detected by it.Â
10.62 MHz
10.62 kHz
5.31 mHz
5.31 mHz
A beam of unpolarized light of intensity I0 is passed through a Polaroid A and then through another polaroid B which is oriented so that its principal plane makes an angle of 45° relative to that of A.The intensity of the emergent light is
I0
I0/2
I0/4
I0/4
Two coherent point sources S1 and S2 are separated by a small distance ‘d’ as shown. The fringes obtained on the screen will be:
point
straight lines
Semi-circle
Semi-circle
The anode voltage of a photocell is kept fixed. The wavelength λ of the light falling on the cathode is gradually changed. The plate current I of the photocell varies as follows:
D.
As λ is increased, there will be a value of λ above which photoelectrons will cease to come out. So, photocurrent will be zero.
In a hydrogen like atom, electron makes the transition from an energy level with quantum number n to another with a quantum number (n – 1). If n >> 1, the frequency of radiation emitted is proportional toÂ
1/n
1/n2
1/n3/2
1/n3/2
The graph between angle of deviation (δ) and angle of incidence (i) for a triangular prism is represented by
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