Upon being struck by 240 nm photons, a material ejects electrons with a maximum

Question

Upon being struck by 240 nm photons, a material ejects electrons with a maximum kinetic energy of 3.22 eV. What is the work function of this material? 1.96 eV 1.65 eV 2.27eV 2.59eV A helium-neon laser emits light at 632.8 nm. If the laser emits 1.99 Times 10^17 photons/second, what is its power output in mW? 40.6 mW 62.5 mW 31.3 mW 500mW A hydrogen atom and a neutron fuse to form deuterium. If the energy released is 3.6 Times 10^-13 J. what is the mass of the deuterium? Take the H atom nucleus as a single proton. 3.4 Times 10^-27 kg 1.3 Times 10^-27 kg 2.0 Times 10^-30 kg 3.3 Times 10^-27 kg If you were in a spaceship traveling at a speed dose to the speed of light (with respect to Earth) you would notice that your mass is different than normal some of your physical dimensions were smaller than normal your pulse rate is different than normal None of these effects occur. More than one of these effects occur. Complete the following nuclear reation: 3H 2H 1_p 1_n How many joules of energy are required to accelerate one kilogram of mass from rest to a velocity of 0.866 c? 1.8 Times 10^17 J 9.0 Times 10^16 jJ 3.0 Times 10^3 J none of the given answers Complete the following nuclear reaction: 1_p 1_n 3_H 2_H Gamma rays are photons with very high energy. How many visible-light photons with a wavelength of 500 nm would you need to match the energy of a gamma-ray photon with energy 89 Times 10^-13 J? 2.2 times 10^6 3.1 Times 10^8 8.5 Times 10^3 1.3 Times 10^10 A photocathode has a work function of 2.2 eV. The photocathode is illuminated with monochromatic radiation whose photon energy is 3.3 eV. The maximum kinetic energy of the photoelectrons produced is closest to: 3.5 Times 10^-19 J 5.3 Times 10^-19 J 1.8 Times 10^-19 J 4.1 Times 10^-19 J 4.7 Times 10^-19 J

Explanation / Answer

Question 27)

Energy of light radiation = Kinetic Energy of photoelectron + Work function

E = h c /

'h' is planks constant; 'c' is speed of light which is equal to 12400 eV

but the wavelength should be in angstroms

so wave length, = 240nm = 2400 angstroms;

E = 12400/2400 = 5.17 eV

therefore, Work function = E - K.E = 5.16eV - 3.22eV

Work function of the material = 1.95 eV.

Hence, option A is correct choice

Question 28)

P = [hc/]*[N/t]

P = [6.626*10-34*3*108 / 632.8*10-9]*[1.99*1017/1]

P = 0.0625 W

P = 62.5 mW

Hence, option B is correct choice

Question 29)

We assume that the following reaction holds:

(proton) + (neutron) ------> deuterium + energy.

The energy comes from mass decay according to

E = mc2.

Or,

m = E/c2.

We have: E = 3.6*10-13 J; c = 3.0*108 m/s

m = 3.6*10-13/(3.0*108)2 = 4.00*10-30 kg.

This is the mass lost during fission.

Now, since:

m (proton) = 1.6726*10-27 kg

m (neutron) = 1.6749*10-27 kg.

We have:

mass (deuterium) = 1.6726*10-27 + 1.6749*10-27 - 4.00*10-30

mass (deuterium) = 3.3435*10-27kg

Hence, option D is correct choice

Related Questions

Navigate

• Browse (All)
• Browse U
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.