An equiconvex lens has a focal length of 20 cm and its radius of curvature is 30 cm. Its refractive index is :

A uniform electric field of 16 N/C exists in the vertically downward direction. The increase in electric potential as one goes up through a height of 75 cm.

In the context of the formation of images by spherical mirror, which of the following statements are correct?
(A) Magnification m is +ve for real images and -ve for virtual images.
(B) f and R are -ve for a concave mirror and +ve for a convex mirror.
(C) Magnification m has no units.
(D) For a real object, u is +ve and v is +ve for real image and -ve for virtual image.
Choose the correct answer from the options given below:

The work function for Tungsten and Sodium are 4.2 eV and 2.3 eV, respectively. If the threshold wavelength for Sodium is 5460 \(\text{\AA}\), then that for tungsten is :

Resistance R1 is with 10 \(\Omega\) resistance in series and is in the first gap of meter bridge with R2 in the second gap. The balance point is at 50 cm. When the 10 \(\Omega\) resistance is removed then the balance point shifts to 40 cm. What is the value of R1?

In an AC circuit, the instantaneous values of emf and current are \( E = 100 \sin(314t) \) V and \( I = \sin(314t + \pi/3) \) A. The average power consumed in the circuit is:

An unpolarised beam of light of intensity \(I_0\) falls on a single polaroid. The intensity of the emergent beam is

Read the following passage carefully.
Restriction enzyme
Restriction enzymes cut the strand of DNA a little away from the center of the palindrome sites, but between the same two bases on the opposite strands. This leaves single stranded portions at the ends. There are overhanging stretches called sticky ends on each strand. These are named so because they form hydrogen bonds with their complementary cut counterparts. This stickiness of the ends facilitates the action of the enzyme DNA ligase. The word palindromes refer to group of letters that forms the same words when read both forward and backward. Restriction endonucleases are used in genetic engineering as molecular scissors.
Palindromes are:

Identify the correct statements for pollen grains
(A) Pollen grain represents male gametophyte.
(B) Pollen grain is a haploid unicellular body.
(C) The hard exine of the pollen is made up of sporopollenin.
(D) The intine of the pollen is composed of oxidative polymers of
carotenoids or carotenoid esters.
Choose the correct answer from the options given below:

In the following examples, select the primary alkyl halide
(A). 1-Bromo-3-methylbutane
(B). 2-Bromo-2-methylbutane
(C). 3-Bromo propene
(D). Chlorophenyl methane
Choose the correct answer from the options given below:

During lockdown, Amit was suffering from heart problem. After proper check-up it was deducted that he has \(45\%\) chance of having heart attack, but yoga and meditation assumed to reduce the chance of heart attack by \(25\%\) and \(20\%\) respectively. He has option to choose any of the two options with equal probabilities.
If Amit goes through one of the two options selected at random and suffers a heart attack, then the probability that he had selected yoga is:

The susceptibility of a paramagnetic material is \( \chi \) at \( 27^\circ \text{C} \). At what temperature will its susceptibility be \( \chi/3 \)?

Area of the region bounded by \(y=-1, y=2, x=y^3\) and \(x=0\) is :