Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

Two parallel wires are located very close to each other. The upper wire is fixed and the lower is free. What should be direction of current of suitable magnitude in both wires to stop the free wire? Give reason also.

If plane of any loop is kept parallel to the magnetic field, then what is the magnitude of magnetic flux associated with the loop?

Two wave pulses identical in shape but inverted with respect to each other are produced at the two ends of a stretched string. At an instant when the pulses reach the middle, the string becomes completely straight. What happens to the energy of the two pulses?

The wavelength of electromagnetic radiation is doubled; how will the energy of a photon change?

What is the magnitude of alternating emf from peak to peak?

A cubical box is to be constructed with iron sheets 1mm in thickness. What can be the minimum value of the external edge so that the cube does not sink in water? Density of iron = 8000kg/m³ and density of water = 1000kg/m³.

Give the physical quantity whose unit is Newton/Coulomb.

Can you accelerate a car on a frictionless horizontal road by putting more petrol in the engine? Can you stop a car going on a frictionless horizontal road by applying brakes?

Four 2cm × 2cm × 2cm cubes of ice are taken out from a refrigerator and are put in 200ml of a drink at 10°C.

1. Find the temperature of the drink when thermal equilibrium is attained in it.
2. If the ice cubes do not melt completely, find the amount melted. Assume that no heat is lost to the outside of the drink and that the container has negligible heat capacity. Density of ice = 900kg-m^-3, density of the drink = 1000kg-m^-3, specific heat capacity of the drink = 4200Jkg^-1-K^-1, latent heat of fusion of ice = 3.4 × 10⁵J-kg^-1.