When a ray of light is incident normally with an incident angle (i) on the surface of thin film. What will be the angle of refraction (r) ?

In the observations of the experiment of scattering of Alpha-particle, Rutherford concluded about the atom that:
(A) the positive charge and the mass of the atom are concentrated at the center called the nucleus
(B) there is positive charge centralized at one point of the size about \( 10^{-10} \text{ m} \) inside the atom
(C) the atom being electrically neutral, it must have negatively charged electrons moving around the nucleus in different orbits
(D) the nucleus is small, electrons move around, there is no space left empty inside the atom
Choose the correct answer from the options given below:

The speed of an electromagnetic wave in a medium of dielectric constant 2.25 and relative permeability 4 is:

The mobility of charge carriers increases with

A magnetic field B exists in a direction perpendicular to the plane of a square loop made of metal wire. The wire has a diameter of 4 mm and a total length of 30 cm. The magnetic field B changes at a steady rate of \( 0.032 \text{ T s}^{-1} \). The induced current in the closed loop is\n(Given: Resistivity of the metal wire is \( \rho = 1.57 \times 10^{-8} \Omega \text{ m} \))

At resonance of a series LCR circuit.
A. Phase difference between \(X_L\) and \(X_C\) is 90\(^\circ\)
B. Source frequency \(= \frac{1}{2\pi\sqrt{LC}}\)
C. Peak current acquires maximum value
D. Inductive reactance is equal in magnitude to Capacitive reactance.
E. The total impedance of the circuit is maximum Choose the correct answer from the options given below:
Choose the correct answer from the options given below:

In the context of the Photoelectric effect, identify the statements which support quantum nature of light.
(A) The electric charge of photoelectrons is quantized
(B) The maximum kinetic energy of photoelectrons depends on the frequency of the incident light, but is independent of its intensity
(C) The photoelectric emission is an instantaneous process without any apparent time lag, even when the incident radiation is made exceedingly dim
(D) There is a minimum frequency of light below which no photoelectrons are emitted
Choose the correct answer from the options given below:

Observe the figure and answer the following:

What is the ploidy of the zygote, antipodal cells and primary endosperm nucleus?

In the process of extraction, gold combines with cyanide in the presence of oxygen and water to make a complex.
The formula of the complex is

The angle between 2 vectors \(\vec{a}\) and \(\vec{b}\) with magnitude 1 and 2 respectively when \(\vec{a} \cdot \vec{b}=1\) is:

Read the following passage carefully and answer the given questions
The separated DNA fragments can be visualized only after staining the DNA with ethidium bromide followed by exposure to UV radiation. Bright orange colored bands of DNA in ethidium bromide stained gel exposed to UV light can be seen. The separated bands of DNA are cut out from the agarose gel and extracted from the gel piece. This step is known as elution. The DNA fragments purified in this way are used in constructing recombinant DNA by joining them with a cloning vector.
The extraction of separated bands of DNA from the gel piece is called:

The Isomerism shown by \([Cr(C_2O_4)_3]^{3-}\) is:

Read the following passage carefully and answer the given questions.
The B-lymphocytes produce an army of proteins in response to pathogens. Each antibody molecule has four peptide chains, two small called light chains and two longer called heavy chains. Virus-infected cells secrete proteins called interferons which protect non-infected cells from further viral infection. Symptoms of allergic reactions include sneezing, watery eyes, running nose and difficulty in breathing. The use of drugs like anti-histamine, adrenalin and steroids quickly reduce the symptoms of allergy.
Lymphoid organs are the organs where origin and/or maturation and proliferation of lymphocytes occur. The primary lymphoid organs are bone marrow and thymus. After maturation the lymphocytes migrate to secondary lymphoid organs like spleen, lymph nodes, tonsils, Peyer's patches of small intestine and appendix. Heroin commonly called smack is chemically diacetylmorphine which is a white, odourless, bitter crystalline compound. This is obtained by acetylation of morphine, which is extracted from the latex of poppy plant Papaver somniferum.
Which one of the following organs is not a secondary lymphoid organ in humans?