Four double convex lenses, with the following specifications are available:

Lens	Focal Length	Aperture
A	100cm	10cm
B	100cm	5cm
C	10cm	2cm
D	5cm	2cm

Which two of the given four lenses should be selected as the objective and eye-piece to construct an astronomical telescope?

In the hydrogen atom, an electron revolves around the nucleus in a circular orbit of radius \( 5.11 \times 10^{-11} \text{ m} \) with a frequency of \( 6.8 \times 10^{15} \text{ Hz} \). The magnetic field at the centre of the orbit is :

A hot electric iron has resistance of \( 88 \, \Omega \) and is used with a 220 V source. The electrical energy consumed in 4 h is:

Speed of Electromagnetic wave is not the same :

The electric field \( E \) associated with a progressive electromagnetic wave is given by \( E = E_0 \sin(kx - \omega t) \). If \( B_0 \) is the amplitude of the magnetic field associated with the wave, then

The phenomenon of polarisation of light confirmed that light waves are

The wavelength will be minimum in the transitions of electrons from:

If \(\vec{a}+\vec{b}+\vec{c}=0,|\vec{a}|=3,|\vec{b}|=25,|\vec{c}|=7\), then the angle between \(\vec{a}\) and \(\vec{b}\) is:

In Young's double slit experiment, the width of one of the two slits is four times the width of the other slit. The ratio of the maximum to the minimum intensity in the interference pattern will be

"The amines which are soluble in water
(A) Methanamine
(B) Ethanamine
(C) Propanamine
(D) Benzylamine
Choose the correct answer from the options given below:"

What will happen during the electrolysis of aqueous solution of \(CuSO_4\) by using platinum electrodes?
A. Copper will deposit at cathode.
B. Copper will deposit at anode.
C. Oxygen will be released at anode.
D. Copper will dissolve at anode.
Choose the correct answer from the options given below:

Read the passage carefully and answer the questions
Optically active polyhydroxy aldehydes or ketones or molecules which provide such units on hydrolysis are called carbohydrates. They can be broadly classified as monosaccharides, disaccharides and polysaccharides depending on their behavior towards hydrolysis. They are also classified as reducing or non-reducing sugars. Another class of biomolecules is proteins which are polymers of twenty different amino acids linked by peptide bonds. Amino acids can be classified as acidic, basic or neutral depending on the relative number of amino and carboxyl groups in their molecule. The essential amino acids cannot be synthesized by our body and hence must be provided through diet. Nucleic acids are the polymers of nucleotides which in turn consist of a base, pentose sugar and phosphate. There are two types of nucleic acids namely, DNA and RNA which differ in the composition of sugar and a base
Four bases present in RNA molecule are

If \(f(x)=x^3 e^{-x}\), then the value of \(f^{\prime \prime}(1)\) is equal to