Atomic and Nuclear Physics Answers

An electron initially at rest is accelerated through a potential difference of∆V and directed into a region with 1) two parallel plates (each parallel to the x z plane) separated by 20 mm with a potential difference of 20 V between them and 2) a uniform 0.5 T magnetic field which is parallel to the plates. The electron is directed into the gap between the parallel plates and not through a hole in one of the plates.

(a) Calculate the minimum ∆V required so that the electron feels no force as it moves through the region between the plates

.(b) Why is this just a minimum?

c) Draw the vectors~E,~B, and~vin the region between the plates for the case of minimum ∆V.

An 'α' particle has an initial velocity of (12 km/s)ˆj+ (15 km/s)ˆkand aconstant acceleration of (2×108m/s2)ˆi in a region where there are uniform electricand magnetic fields. If~B= (4×10−4,0,0) T, what is~E?

A long, straight wire 9.27 mm in diameter carries 147 A distributed uniformly over its cross section.Find the magnitude of the magnetic field (also called the magnetic field strength)

(a) 2.50 mm from the wire’s axis and

(b) 7.50 mm from the axis

The line integral of the magnetic field on a closed path surrounding a wire has the value 10.0μT·m. What is the current in the wire?

A single-turn square loop 20.0 cm on a side carries a 1.5 A current.

(a) What’s the loop’s magnetic dipole moment?

(b) What’s the magnitude of the torque the loop would experience if it was in a 2.3T magnetic field with the loop’s dipole moment vector at 60^◦ to the field?

What’s the current in a long wire if the magnetic field strength (magnitude-of the magnetic field) 1.2 cm from the wire’s axis is 67μT?

A single-turn wire loop is 2.0 cm in diameter and carries a 650 mA current.Find the magnetic field strength:

(a) at the loop centre

(b) on the loop axis, 20 cm from the centre

What is the range of electromagnetic force?

What is the approximate value for the diameter of an atom?

A broken leg with a mass of 5kg receives an equivalent dose of 0.5mSv. If the X-ray energy is 50keV,how many x-ray photons were absorbed?