In an experiment with a convex lens, the length of an image is 1 cm, and the object length is 5 cm. If the object is placed at a distance of 40 cm from the lens, then the focal length of the lens is

In an electromagnetic wave, the amplitude of magnetic field is \( 1.1 \times 10^{-6} \text{ T} \). What is the amplitude of electric field?

The ratio of nuclear densities of two nuclei having mass numbers A and 8 A, respectively is

A plane wave is incident on a concave mirror of radius R. The shape of the reflected wavefront will be

Arrange the following electromagnetic waves in the increasing order of their energy:
(A) infrared rays
(B) AM radio waves
(C) y - rays
(D) Microwaves
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A radio wave of wavelength 300 m can be transmitted by a transmission center. A condenser of capacity \( 2.5 \mu F \) is available. The inductance of the required coil at resonance is
(Given: \( \pi^2 = 10 \))

Choose the correct statements from the following:
A. The minimum energy required to free the electron from the ground state of the hydrogen atom is 13.6 J
B. The principle quantum number n labels the stationary states in the ascending order of energy
C. Bohr gave the basic idea of discrete energy levels
D. de Broglie hypothesis provided an explanation for Bohr's second postulate for the quantization of angular momentum of the orbiting electron
E. line spectrum provides useful information about the atomic structure.
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Differentiation of \(\frac{x^3}{1-x^3}\) with respect to \(x^3\) is equal to:

The magnetic field produced at the centre of circular loop of diameter 4 cm is \( 6.28 \times 10^{-5} \text{ T} \). The current required to flow in the loop is : (\( \mu_0 = 4\pi \times 10^{-7} \text{ N A}^{-2} \))

Which of the following compound will not undergo Azo coupling reaction?

Which one of the followings is a hormone releasing IUD?

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Organic compounds containing carbon -oxygen double bonds ( \(C = O\) ) are called carbonyl compounds. These are highly polar molecules. Hence, their boiling points are higher than hydrocarbons and ethers. Aldehydes can be prepared from dehydrogenation or oxidation of alcohols and by reduction of acylhalides. Ketones are prepared by oxidation of secondary alcohols or by hydration of alkynes etc. Aldehydes and ketones undergo nucleophilic addition reaction with the number of nucleophiles such as HCN , NaHSO 3 ammonia derivatives. Carboxylic acids are prepared by the oxidation of primary alcohols, aldehydes and alkenes, by hydrolysis of nitriles. Carboxylic acids are more acidic than alcohols and phenols.
The correct sequence of reagents for the conversion of \(3\)-nitrobromobensene to \(3\)-nitrobensoic acid is:

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Nitrogen differs from rest of the members of group 15 due to its small size, high electronegativity, high ionization enthalpy and non-availability of d orbitals. Nitrogen has unique ability to form pa - pa multiple bonds with itself and with other elements having small size and high electronegativity. Heavier elements of this group do not form pa - pr bonds as their atomic orbitals are so large and diffuse that they cannot have effective overlapping.
Planar structures with \(N - N\) single bond are shown by
A. \(N _2 O _3\)
B. \(N _2 O _4\)
C. \(N _2 O _5\)
D. \(N _2 O\)
E. \(NO\)
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