In X-ray tube when the accelerating voltage V is halved, the difference between the wavelength of Ka line and minimum wavelength of continuous X-ray spectrum
|
(a) Remains constant |
(b) Becomes more than two times |
|
(c) Becomes half |
(d) Becomes less than two times |
(d) Becomes less than two times
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Optical fibres are related with
|
(a) Communication |
(b) Light |
(c) Computer |
(d) None of these |
Four capacitors are connected as shown in the figure. Their capacities are indicated in the figure. The effective capacitance between points x and y is (in μF)
|
(a) |
(b) |
(c) |
(d) 2 |
A ray of light is incident at the glass–water interface at an angle i, it emerges finally parallel to the surface of water, then the value of 
would be
|
(a) (4/3) sin i |
(b) 1/sin i |
(c) 4/3 |
(d) 1 |
Match the List I with the List II from the combination shown. In the left side (List I) there are four different conditions and in the right side (List II), there are ratios of heat produced in each resistance for each condition :
|
List I |
List II |
||
|
(I) |
Two wires of same resistance are connected in series and same current is passed through them |
(A) |
1 : 2 |
|
(II) |
Two wires of resistance R and 2R ohm are connected in series and same P.D. is applied across them |
(B) |
4 : 1 |
|
(III) |
Two wires of same resistance are connected in parallel and same current is flowing through them |
(C) |
1 : 1 |
|
(IV) |
Two wires of resistances in the ratio 1 : 2 are connected in parallel and same P.D. is applied across them |
(D) |
2 : 1 |
|
(a) I – B; II – A; III – C; IV - D |
(b) I – C; II – D; III – C; IV - D |
|
(c) I – B; II – D; III – A; IV - C |
(d) I – A; II – B; III – D; IV - C |
A lens of focal power 0.5 D is
|
(a) A convex lens of focal length 0.5 m |
|
(b) A concave lens of focal length 0.5 m |
|
(c) A convex lens of focal length 2 m |
|
(d) A concave lens of focal length 2 m |
A tank is filled with benzene to a height of 120 mm. The apparent depth of a needle lying at a bottom of the tank is measured by a microscope to be 80 mm. The refractive index of benzene is
|
(a) 1.5 |
(b) 2.5 |
(c) 3.5 |
(d) 4.5 |
The figure below shows currents in a part of electric circuit. The current i is
|
(a) 1.7 amp |
(b) 3.7 amp |
(c) 1.3 amp |
(d) 1 amp |
