Answer:
<h2>
E = 2.8028*10⁻¹⁹ Joules</h2>
Explanation:
The minimum energy needed to eject electrons from a metal with a threshold frequency fo is expressed as E = hfo
h = planck's constant
fo = threshold frequency
Given the threshold frequency fo = 4.23×10¹⁴ s⁻¹
h = 6.626× 10⁻³⁴ m² kg / s
Substituting this value into the formula to get the energy E
E = 4.23×10¹⁴ * 6.626 × 10⁻³⁴
E = 28.028*10¹⁴⁻³⁴
E = 28.028*10⁻²⁰
E = 2.8028*10⁻¹⁹ Joules
Answer:
2.7 s
Explanation:
The period of the motion of a massless loaded spring is given by
where m is the mass of the load and k is the force or spring constant.
Using values in the question and converting to appropriate units,
Answer:
-2
Explanation:
Since its a compound, it's charge is 0.
So, there are 2 Fe and 3 Oxygen,
let x = oxidation number of oxygen
2(+3) + 3x =0
x =-2
Side note : even if the oxidation number is positive, make sure to put the positive sign like how you would in numbers
Just treat the bead as a point charge.
E = kq/r^2, and E points away from the center of the sphere since the charge is positive.
