A galvanometer having a resistance of 20 $$\Omega $$ and 30 divisions on both sides has figure of merit 0.005 ampere/division. The resistance that should be connected in series such that it can be used as a voltmeter upto 15 volt, is:

In a photoelectric experiment, the wavelength of the light incident on a metal is changed from 300 nm to 400 nm. The decrease in the stopping potential is close to: ($${{{hc} \over e}}$$ = 1240 nm eV)

A thermometer graduated according to a linear scale reads a value x₀ when in contact with boiling water, and x₀/3 when in contact with ice. What is the temperature of an object in ^oC, if this thermometer in the contact with the object reads x₀/2 ?

A paramagnetic substance in the form of a cube with sides 1 cm has a magnetic dipole moment of 20 $$ \times $$ 10^–6 J/ T when a magnetic intensity of 60 $$ \times $$ 10³ A/m is applied. Its magnetic susceptibility is