Atomic and Nuclear Physics Answers

A metal rod of length 40.0 cm at 20°C is heated through a temperature of 45°C if the new length of the rod

is 40.05 cm calculate its linear expansivity

ACTIVITY 1.1. WRITE THE NUCLEAR REACTION INVOLVED IN THE SYNTHESIS OF EACH OF THE FOLLOWING NEW ELEMENTS.

A.Curium(Z=96) was formed by reacting Pu-239 with alpha particles ⁴²He,it has a half -life of 162 days.

B.Mendelevium(Z=101) was formed by reacting En-253 with alpha particles.

C.Meitnerium(Z=109) was formed by cold fusion which involves the combination on Bi and Fe nuclides at ordinary temperature.

The intrinsic temperature of a semiconductor is the temperatures at which the intrinsic

carrier concentration equals the impurity concentration. Find the intrinsic temperature for a

silicon sample doped with 1015 phosphorus atoms/cm3

.

Calculate the location of Ei in silicon at liquid nitrogen temperature (77 K), at room

temperature (300 K), and at 100 °C (let mp =1.0 m0 and mn= 0.19 m0). Is it reasonable to assume

that Ei is in the center of the forbidden gap?

Derive an expression for density of state for particle 3-D crystal having mass m with

energy ranging between E and E + dE

A spring stretches 14 cm when an object weighing 28 N is hung from it . what is the spring constant.

The Earth may be considered to be a uniform sphere of radius 6.38 × 106 m. Its mass is assumed to be concentrated at its centre.

Given that the gravitational field strength at the Earth’s surface is 9.81 N kg–1, show that the mass of the Earth is 5.99 × 1024 kg.

What is the force between two protons that are separated by 1.0 mm? The charge of a proton is 1.6 × 10^-19 C.

The Q value of the Na23 (n,α) F20 reaction is -5.4MeV. Determine the threshold energy of the neutrons for this reaction (22.9898u, 18.9964u, 4.0039u, 1.008665u are the masses of Na23, F20 α and n respectively).

How many grams of an unknown gas having a molecular weight of 24.34 g/mol will be produced at STP?