What is the path difference for destructive interference (if n is an integer)?

Resolving power of a telescope can be increased by increasing :

An electric motor operating at a 100 V D.C. supply draws a current of 12 A. If the efficiency of the motor is 30%, calculate the resistance of its winding.

A cube is placed at the origin as shown in the figure. The electric field in the region is given as \( \vec{E} = (200 x^2 \hat{i}) \frac{\text{N}}{\text{C}} \). The flux coming out of the cube is:

A conducting sphere of radius R is given a charge Q. What is the electric field and the electric potential at the centre of the sphere?

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 ?

Arrange the following steps \(( A , B , C\) and D \()\) in proper sequence to determine the index correction in the given arrangement.

(A) The difference between the two gives the correction to be applied to the observed distance.
(B) The positions of the uprights are read on the scale. Their difference gives the observed distance between tip of the pin and the pole of the mirror.
(C) A thin straight index needle OP is placed so that its one end O touches the tip of the pin and the other end P touches the pole of the mirror.
(D) Length of the needle OP is measured by placing it on the scale which is the actual distance between the points in question.
Choose the correct answer from the options given below:

In which of the following, the time series may show the gradual shifts to relatively higher or lower values over a long period of time?

If the entire current produced is used for the electrodeposition of silver (atomic weight \(=108 g / mol\) ), the amount of silver deposited will be:

The large holes in 'Swiss cheese' are due to -

Match List - I with List - II.

List 1	List 2
(A) Infra red waves	(I) to detect fracture of bones
(B) Radio waves	(II) absorbed by the ozone layer of atmosphere
(C) X-rays	(III) to treat muscular pain
(D) Ultraviolet rays	(IV) for broadcasting

Choose the correct answer from the options given below :

Identify the statement which do not hold true for Deoxyribose Nucleic Acid.
A. Only purine bases are present in DNA.
B. Deoxyribose sugar is present
C. A nitrogenous base is linked to the \(1^{\circ} C\) pentose sugar through N glycosidic linkage.
D. Phosphate group is linked to OH of \(4^{\circ} C\) of a nucleotide.
Choose the correct answer from the options given below:

Which of the following statements is correct for the identification of a diode using a multimeter?