A uranium nucleus (charge 92e, mass 238 n) at rest decays into a thorium nucleus
ID: 1550550 • Letter: A
Question
A uranium nucleus (charge 92e, mass 238 n) at rest decays into a thorium nucleus (charge 90e, mass 234 u) and an alpha partial (charge +2e, mass 4 u). just after the decay the partial are at rest and separated by 7.4 times 10^-15 m. Find the kinetic energy of each decay particle when they are infinitely far apart. Do not assume that the thorium stays at rest. A disk of radius b has a concentric hold of radius alpha. There is a uniform surface charge density sigma. Find the potential at a point on the axis of the disk at a distance y from the counter. (I) In a NaCl crystal, Na+ and Cl^- ions lie on a three dimensional cubic array, as shown in fig, 25.33. the nearest neighbor of any ion is at a distance 2.82 times 10^33 m. find the potential energy of a Na^+ ion (a) including only the contributions of the six nearest neighbors; (b) by including the contributions of the twelve next nearest neighbors. A beam of electrons is accelerated by 20 kV and bombards a 500-g tungsten target with 4 times 10^16 electrons per second. Assuming the 30% of the energy of the electrons goes into heating the target, how long does it take for the temperature of the target to rise by 10 degree C? (the specific heat of tungsten is 134 J/kg K.) a metal sphere of radius R_1 has a charge Q_1. It is enclosed by a conducting spherical shell of radius R_2 that has a charge -Q_2; sec Fig. 25.34. determine; the potential V-1 of the inner sphere the potential V_2 of the outer sphere; the potential difference V_1 - V_2 - (d) under what condition is V_1 - V_2? A balloon of radius R has a uniform surface chare density sigma C/m^2. Show that the surface experiences an electrostatic force per unit area equal to sigma^2/2e_q, N(m^2. A coaxial cable has an inner wire of radius a with linear charge density lambda C/m surrounded by a cylindrical of radius b carrying a linear charge density -lambda. Use the electric field (E = k lambda/r) between the wire and the sheath to show that the potential difference between them is V(b) - V(a) = -k lambda ln (b/a)Explanation / Answer
Given that,
Potential difference V = 20 kV = 20000 volt
Mass of target tungsten, m = 500 g = 0.5 kg
Number of electrons bombarded to the target N = 4*1016
Specific heat of tungsten C = 134 J /kg K
dt = 10 deg
Velocity of the electron v = sqrt(2*V*q / m)
v = sqrt [2(20000)(1.6*10-19) / (9.1*10-31)]
v = 83.86*106 m/s
Kinetic energy of one electron
KE = (1/2)*m*v 2
KE = 0.5*9.1*10-31 * (83.86*106 ) 2
KE = 3.2*10-15 J
Thermal energy by one electron Q' = 30 % of KE
Q' = 0.3( 3.2*10-15)
Q' = 9.6*10-16 J
Heat required to raise this temperature Q = m*C*dt
Q = 0.5*134*10 = 670 J
Number of electrons required to raise the temperature N ' = Q / Q '
N ' = (670) / (9.6*10-16)
N' = 6.97*1017
Required time t = N '/ N
t = 6.97*1017 / 4*1016
t = 17.44 s
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.