Class 12th

Which among the following is malachite?

Determine the lowest energy of photon emitted in Balmer series of hydrogen atom.

If vapour pressure of two liquids A and B in pure state are 400 and 500 mm of Hg respectively then mole fraction of A in vapour phase of solution obtained by mixing equal moles of A and B is

Which of the following aqueous solution has highest boiling point?

Packing efficiency of fcc lattice is

The first co-ordination number of Cs⁺ in CsCl lattice is

The length of a potentiometer wire is ?. A cell of emf E is balanced at a length ?/4 from the positive end of the wire. If the length of the wire is increased by ?/2, at what distance will the same cell give a balanced point? (Potentiometer battery is ideal)

The spectrum of a black body at two temperature 127°C and 527°C is shown in the figure. Let A1 and A2 be the areas under the two curves respectively. The value A_1/A_{2 is:}

If a star emitting light of wavelength 500 nm is moving towards earth with a velocity of 1.5 ´ 106 m/s then the shift in the wavelength due to doppler's effect will be:

When a metallic surface is illuminated with radiation of wavelength l, the stopping potential is V. If the same surface is illuminated with radiation of wavelength 2l, the stopping potential is  V . The threshold wavelength metallic surface is