Two convex lenses of same focal lengths but of aperture A₁ and A₂ (A₂ < A₁)_, are used as the objective lenses in two astronomical telescopes having identical eye-pieces. The ratio of their resolving powers is

• $\frac{{\mathrm{A}}_1}{{\mathrm{A}}_2}$

• 1 : 1

• $\frac{{\mathrm{A}}_2}{{\mathrm{A}}_1}$

• data insufficient

A beam of light converges at a point P. A concave lens of focal length 16 cm is placed in the path of this beam 12 cm from P. The location of the point, from the lens, at which the beam would now converge is

• 48 cm

• 45 cm

• 80 cm

• 90 cm

A nucleus undergoes β-decay. The mass number and  atomic number change as

• mass number and atomic number both increases

• mass number remain same and atomic number increases

• mass number increases and atomic number remain same

• mass number and atomic number both decreases

54.

The graph given below showing the variation of stopping potential with the frequency of incident radiation for two different photosensitive materials having work functions W₁ and W₂ ( W₁ < W₂ ).

   

The slope of graph showing the variation of stopping potential with the frequency of incident radiation gives the value of

• h/e where, h is Planck's constant and e electronic charge

• h i.e, Planck's constant

• e i.e, electronic charge

• None of the above

In Young's double slit experiment, monochromatic light of wavelength 600 nm illuminates  the pair of slits and produces an interference pattern in which two consecutive bright fringes are separated by 10 mm. Another source of monochromatic light produces the interference pattern in which of the two consecutive bright fringes are separated by 8 mm. The wavelength of light from the second source is

• 448 nm

• 450 nm

• 480 nm

• 580 nm

Light passes through two polaroids P₁ and P₂ with pass axis of P₂ making an angle θ with the pass axis of P₁.  That value of θ for which the intensity of emergent light is zero.

• 45°

• 90°

• 30°

• 60°

If the angle between the axis of polarizer and the analyser is 45 degree, the ratio of the intensities of original light and the transmitted light after passing through the analyser is

• 2 : 1

• 1 : 2

• 2 : 3

• 1 : 1

A full wave rectifier circuit along with the output is shown in the figure. The contribution (s) from the diode 1 is ( are )

• C

• A , C

• B , D

• A, B , C , D

Two identical p-n junctions may be connected in series with a battery in three ways as shown in the figure.

The potential drops across the two n-p junctions are equal in

• circuit 1 and circuit 2

• circuit 2 and circuit 3

• circuit 3 and circuit 1

• circuit 1 only

A transistor is used in common emitter mode as an  amplifier, then

• the base emitter junction is forward unbiased

• the base emitter junction is reverse biased

• the input signal is connected in series with the voltage applied to bias of the base emitter junction

• the input signal is connected in series with the voltage applied to bias the emitter collector junction