Two circular coils of diameter 10 cm and 20 cm, carrying equal currents have the same number of turns. The ratio of magnetic fields produced at the center of coils, respectively will be

A cell of emf E is connected across an external resistance R. When a current I is drawn, the potential difference across the electrodes drops to V. The internal resistance r of the cell is :

Identify the incorrect statement.
(A) Power meters work on the principle of Eddy currents.
(B) Induction furnace uses eddy currents to produce heat.
(C) Eddy currents can be used to produce braking force in moving trains.
(D) Eddy currents are produced in a steady magnetic field.
Choose the correct answer from the options given below :

In a radioactive decay, neither the atomic number nor the mass number changes. Which of the following is emitted in the decay?

In a potentiometre, the balanced point is obtained when :

When the light of frequency \(2 \nu_0\) (where \(\nu_0\) is the threshold frequency) is incident on a photosensitive material, the maximum velocity of electrons emitted is \(v_1\). When the frequency of the incident radiation is increased to \(3 \nu_0\), the maximum velocity of emitted electrons from the same material is \(v_2\). The ratio of \(v_1\) to \(v_2\) will then be :

Read the following statements regarding energy levels, and identify the correct statements.
(A) The energy of an atom is least when its electron is revolving in an orbit closest to the nucleus
(B) the energy levels of the excited states come closer and closer together as principal quantum number increases
(C) ionisation energy of the hydrogen atom is the minimum energy required to free the electron from the ground state of the hydrogen atom
(D) as the excitation of hydrogen atom increases, the value of minimum energy required to free the electron from the excited atom decreases.
Choose the correct answer from the options given below:

Arrange the following steps of rDNA technology in correct sequence.
(A) Amplification of gene by PCR
(B) Insertion of rDNA into host cell using vector
(C) Isolation of the genetic material from the cell
(D) Cutting the DNA at specific location
Choose the correct answer from the options given below :

The corner points of the bounded feasible region determined by the system of linear constraints are (0,10), (5, 5), (15, 15), (0, 20). Let \(z=p x+q y\) where \(p, q>0\). Then the condition on p and q so that the maximum value of z occurs at (15, 15) and (0, 20) is

5 M sugar solution is \(30 \backslash \%\) sugar by mass. Calculated density of the solution will be, given that molecular weight of sugar is \(342 g mol ^{-1}\).

Interstitial transition metal compounds
(A) have higher melting points than those of pure metals.
(B) have more reactivity than those of pure metals.
(C) are non-stoichiometric compounds.
(D) formed when small atoms like H, C or N are trapped inside the crystal lattice of the metals.
Choose the correct answer from the options given below:

For the given five values 16, 25, 19, 34, 46, the three years moving averages are:

Total number of isomers for the complex \([\text{FeCl}_2 (\text{C}_2\text{O}_4)_2]^{4-}\) is: