There are two conductor X and Y of the same material, having length l and 4l, and radii r and r/4 respectively. The ratio of their resistivity is :

The armature coil of a generator has 20 turns and its area is \( 0.127 \, \text{m}^2 \). How fast approximately should it be rotated in a magnetic field of \( 0.2 \, \text{Wb m}^{-2} \) so that the peak value of induced emf is 160 V?

Which of the following statements is not true with reference to a potentiometer ?

A positively charged particle moving along + X axis, enters a region of uniform magnetic field directed vertically upward in + Z direction. The particle will

The correct formula for range of a transmitting antenna of height '2h' is: (Given R = radius of the Earth)

A transformer has 1000 turns in the primary and 2000 turns in its secondary winding. The primary voltage is 200 V and the load across the secondary is \(100 \Omega\). If the transformer is assumed to be ideal, then the value of current in the primary is

Choose the correct relation between focal length f and radius of curvature R of a convex mirror from the following:

The solution of the differential equation \(\frac{d y}{d x}=\sqrt{\frac{y}{x}}\) is

Area of the region bounded by the curve \(y=\cos x\) between \(x=0, x=\pi\) and \(x\)-axis is :

Area (in sq. units) of the region bounded by curves \(y^2=x\) and \(x=4\) is

A current is uniformly distributed across the cross-section of cylindrical wire of radius R = 4 mm with current density \( J = 2.5 \times 10^5 \text{ Am}^{-2} \). The amount of current flowing through the outer portion of the wire between radial distance R/2 and R is

The differential equation of the family of lines through the origin is:

Answer the question on the basis of passage given below:
Proteins are the polymers of about twenty different a-amino acids which are linked by peptide bonds. Proteins perform various structural and dynamic functions in the organisms. Proteins which contain only a-amino acids are called simple proteins. The secondary or tertiary structure of proteins get disturbed on change of pH or temperature and they are not able to perform their functions. This is called denaturation of proteins. Enzymes are biocatalysts which speed up the reactions in biosystems. Vitamins are accessory food factors required in the diet. They are classified as fat soluble (A, D, E and K) and water soluble (B group and C). Deficiency of vitamins leads to many diseases. Nucleic acids are the polymers of nucleotides which in turn consist of a base, a pentose sugar and phosphate moiety. Nucleic acids are responsible for the transfer of characters from parents to offsprings. There are two types of nucleic acids DNA and RNA. DNA contains a five carbon sugar molecule called 2-deoxyribose whereas RNA contains ribose.
Deficiency of which of following vitamins can cause scurvy (loosening and bleeding of gum)?