A convex lens has 20 cm focal length in air. Its focal length in water would be (Given : Refractive index of water = 1.33, refractive index for glass = 1.5)

The following statements are given related to Wheatstone Bridge:
1. when Wheatstone Bridge is balanced, no current flows through the galvanometer arm.
2. Wheatstone Bridge works on the principle of Kirchhoff's law.
3. Being a null method based experiment, the result is free from the effect of extra resistances (cell resistance) of the circuit
4. Wheatstone Bridge is most sensitive when all the four resistances are nearly of the same magnitude.
Choose the correct answer from the options given below:

If charge is moving parallel to uniform magnetic field, its path will be:

In an AC generator when the plane of the armature is perpendicular to the magnetic field, what will be the magnitude of the magnetic flux passing through the coil and the emf induced in the coil be ?

In a Young's double slit experiment, two slits are separated by 3 mm and the screen is placed 1.5 m away. The distance between two consecutive minima for a light of wavelength 420 nm is

In a diffraction pattern due to a narrow slit of width a, alternate dark and bright fringe pattern is obtained on a screen kept at distance D from the slit. Choose the correct option.
(A) The angular width of central maximum is given by 2D/a, linear width is given by 2D\lambda/a
(B) When the size of aperture, a is quite large, the diffraction effect is negligible,
(C) For light of smaller wavelength, angular width of central maximum increases, while linear width decreases,
(D) Angular width of central maximum does not decrease while linear width decreases on decreasing distance of screen from slit.
Choose the correct answer from the options given below:

An electron is projected into a magnetic field of flux density \( 10 \text{ Wb/m}^2 \) with a velocity of \( 3 \times 10^7 \text{ m/s} \) at an angle of \( 30^{\circ} \) to the field. The magnetic force on the electron is:

Speed of Electromagnetic wave is not the same :

Three charges \(+4 q, Q\) and \(q\) are placed along \(x\)-axis at points, \(x=0, I / 2\) and I respectively. The value of Q to make the net force on \(q\) to be zero :

Which statement is correct for solutions?

The rise in prices before festivals is an example of

Select the statements which hold true for transgenic plants.
A. They are produced by arresting spindle formation during cell division.
B. They are formed by inducing gene mutation.
C. They are produced by introducing foreign gene through rDNA technology.
D. Bt cotton is a transgenic plant.
Choose the correct answer from the options given below:

"The rate constant of a first order reaction follows the equation 
 \(log\ k = 8.0 - \frac{5000}{T}\)
 The activation energy \((E_a)\) for the reaction is:
 (Given \(R = 8.3\ JK^{-1}\ mol^{-1}\))"