A metal plates 5 millimetre thick and 10 centimetre square has a temperature difference of `35^@C` between its urfaces. If 1820 calories of heat are transimitted every second, what is the co-efficient of thermal conductivity of the metal?

The Millikan oil-drop experiment enabled the charge on the electron to be deterined. Two parallel metal plates P and Q are situated in a vaccum. The plates are horizontal and separated by a distance of 5.4 mm, as illustrated in fig. The lower plate P is earthed. The potential difference between the plates can be varied. An oil droplet of mass 7.7 xx 10^-15 kg is oserved to remain stationary between the plates , when palte Q is a t a potential of +850 suggest why plates p and Q must be parallel and horizontal and calcualte the charge with its gin, on the oil droplet.

For the harmonic travelling wave y =2 cos 2pi(10t-0.0080x+3.5) where x and y are in cm and t is second. What is the phase difference between the osciallition of a particle located at x=100 cm, at t=Ts and t=5s?

A small particle carrying a negative charge of 1.6xx10^-19 C is suspended in equilibrium between the horizontal metal plates 5 cm apart, having a potential difference of 3000 volt across them. Find the mass of the particle.

A cylinder of diameter exactly 1 cm at 30^@C is to be slided into a hole in a steel plate. The hole has a diameter of 0.99970 cm at 30^@C . To what temperature must the plate be heated? For steel alpha = 1.1 xx 10^-5 ^@C^-1