Class 12th

Consider the reaction sequence given below:

Which of the following statements is true:

The number of chiral carbons present in the molecule given below is 

The metal mainly used in devising photoelectric cells is:

The metal mainly used in devising photoelectric cells is:

Consider the following reactions

In a reactor, 2 kg of ₉₂U²³⁵ fuel is fully used up in 30 days. The energy released per fission is 200MeV. Given that the Avogadro number, N = 6.023 * 10²⁶ per kilo mole and 1eV = 1.6 * 10⁻¹⁹ J. The power output of the reactor is close to:
(A) 60MW

A beam of protons with speed 4 * 10⁵ ms⁻¹ enters a uniform magnetic field of 0.3 T at an angle of 60° to the magnetic field. The pitch of the resulting helical path of protons is close to: (Mass of the proton = 1.67 * 10⁻²⁷ kg, charge of the proton = 1.69 * 10⁻¹⁹ C)

An amplitude modulated wave is represented by the expression vₘ = 5(1 + 0.6cos 6280t)sin(211 * 10⁴t) volts. The minimum and maximum amplitudes modulated wave are respectively

A 5µF capacitor is charged fully by a 220 V supply. It is then disconnected from the supply and is connected in series to another uncharged 2.5µF capacitor. If the energy change during the charge redistribution is X/100 J then value of X to the nearest integer is:

When radiation of wavelength λ is used to illuminate a metallic surface, the stopping potential is V. When the same surface is illuminated with radiation of wavelength 3λ, the stopping potential is V/4. If the threshold wavelength for the metallic surface is nλ then value of n will be: