Light of wavelength 3500Å is incident on two metals A and B whose work functions are 3.2 eV and 1.9 eV respectively. Which metal will emit photoelectrons? (a) A
(b) B
(c) Both A and B
(d) Neither A nor B

(c) Both A and B

Explanation:

Given;

wavelength of the incident light, λ = 3500 Å = 3500 x 10⁻¹⁰ m

The energy of the incident light is given by;

E = hf

where;

h is Planck's constant = 6.626 x 10⁻³⁴ J/s

f is frequency =  c / λ

Work function is the minimum amount of energy required to liberate electrons from a metal surface.

The work function of metal A is 3.2 eV and

Th e work function of metal B is 1.9 eV

Both work functions are less than the incident energy of the light calculated as 5.68eV.

Thus, both metals will emit photoelectrons.

(c) Both A and B

the first, second, and fifth options

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation: