Lower half of a convex lens is opaque. The image of an object placed in front will :

Arrange the following electromagnetic waves in the increasing order of their energy:
(A) infrared rays
(B) AM radio waves
(C) y - rays
(D) Microwaves
Choose the correct answer from the options given below:

Four equal charges \(Q\) are placed at the four corners of a square of side 'a'. Work done in removing a charge \(-Q\) from its centre to infinity is :

The amplitude of the magnetic field of a harmonic electromagnetic wave in vacuum is \(B_0=610 nT\). The amplitude of the electric field of the wave is:

According to Bohr's Model :
(A) The radius is directly proportional to 'n'.
(B) The speed is directly proportional to \(\frac{1}{n} \) .
(C) The magnitude of total energy is directly proportional to \(\frac{1}{n^2} \).
(D) The radius is directly proportional to \(n^2\)

A positive charge is moving vertically upwards. When it enters a region of magnetic field directed towards north, the direction of force on the charge would be

The following that is not transported by Electromagnetic waves is :

Two particles x and y having equal charge, after being accelerated through the same potential difference, enter a region of a uniform magnetic field. They describe circular paths of radii \( R_1 \) and \( R_2 \), respectively. The ratio of the mass of x to that of y is:

Identify the incorrect statement about the genetic modification.

Which one of the following regions is not present in transcriptional unit of DNA

The forbidden energy gaps in conductors, semiconductors and insulators are \( (E_g)_c, (E_g)_s \) and \( (E_g)_I \) respectively. What is the relation among them ?

Amines are reactive in nature, mainly due to difference in electronegativity between Nitrogen and Hydrogen and, due to lone pair of electrons on Nitrogen. Amines behave like nucleophiles and as good lewis bases and there are various reactions to support this. Different degree of amines differ in their reactivity due to steric hinderance and electronic effects. Aromatic amines are less basic due to + R effect, hence have higher pkb value than aliphatic amines. Basic strength of amines also depends on stability of corresponding conjugate acid in aqueous medium.
Which of the following will be having lowest \(p K_b\) in gaseous medium?

If \(A=\left[\begin{array}{lll}a & a & a \\ 0 & a & a \\ 0 & 0 & a\end{array}\right]\), then |adj A| is equal to