If we double the number of turns of coil in a moving coil galvanometer, its voltage sensitivity will :

A source of electromagnetic wave of 400 W produces \(10^{20}\)photons per second. Identify the part of the electromagnetic spectrum to which these radiations belong:

If a p-n junction is forward biased, then what is the direction of diffusion and drift current across the junction?

An angular magnification of 30 X is desired using an objective lens of focal length 1.25 cm and an eyepiece of focal length 5 cm. What should be the separation between objective and eyepiece when the final image is formed at the near point ?

Which of the following will have the smallest radius of first orbit (n = 1)

Match List-I with List-II

List-I (Optical instrument)	List-II (Magnifying power)
(A) Magnifying power m of a simple microscope	(I) \( m = 1 + (D/f) \)
(B) Magnifying power m of a simple microscope if the image is at infinity	(II) \( m = (L/f_0) \times (D/f_e) \)
(C) Magnifying power m of a compound microscope	(III) \( m = f_0 / f_e \)
(D) Magnifying power m of a telescope	(IV) \( m = D/f \)

Choose the correct answer from the options given below:

Forward biasing of a p-n junction

The series of hydrogen spectrum which lies in the visible region is :

An iron ring of relative permeability \( \mu_r \) is introduced inside a toroidal solenoid having n turns per meter. If the current in the solenoid is I, then the magnetic field in the ring is :

The genetic disorder caused due to presence of an additional copy of the chromosome number 21 is:

A medicinal plant growing in different Himalayan ranges shows different potency and concentration of the active chemical (reserpine) that the plant produces. Identify the plant:

Identify the correct statement(s) among the following:
(A) If three electrical cells each of emf, E and internal resistance r are connected in series to a resistance R, the current drawn from them is 3E/(R+3r).
(B) If these three cells are connected in parallel combination, across resistance R then the current drawn will be E/(3R+r).
(C) If the two cells are connected in series and then one in parallel which are then connected across resistance R, then the current drawn will be 2E/(2R+2r).
(D) In a mixed grouping of cells, current will be maximum when total external resistance is equal to total equivalent internal resistance.
Choose the correct answer from the options given below :

In a photoelectric experiment, the wavelength of incident light is increased from \( 5 \times 10^{-10} \text{ m} \) to \( 9 \times 10^{-10} \text{ m} \), while the intensity of radiation remains the same. Choose the correct statement from the following.