Answer:
B. An Iron Bar place in a room becomes cooler than its surroundings.
Newton has 3 Laws specifically The Three Laws of Motion
Answer:
The maximum wavelength of light that could liberate electrons from the aluminum metal is 303.7 nm
Explanation:
Given;
wavelength of the UV light, λ = 248 nm = 248 x 10⁻⁹ m
maximum kinetic energy of the ejected electron, K.E = 0.92 eV
let the work function of the aluminum metal = Ф
Apply photoelectric equation:
E = K.E + Ф
Where;
Ф is the minimum energy needed to eject electron the aluminum metal
E is the energy of the incident light
The energy of the incident light is calculated as follows;

The work function of the aluminum metal is calculated as;
Ф = E - K.E
Ф = 8.02 x 10⁻¹⁹ - (0.92 x 1.602 x 10⁻¹⁹)
Ф = 8.02 x 10⁻¹⁹ J - 1.474 x 10⁻¹⁹ J
Ф = 6.546 x 10⁻¹⁹ J
The maximum wavelength of light that could liberate electrons from the aluminum metal is calculated as;
Answer:
The value of current through the rod becomes half

Explanation:
As per Ohm's law we know that the current through a resistor is given as

here we know that

here we know that the length of the cylinder is L and area is A so the value of current through the rod is given as

now we have change the length of the conductor to twice of initial value and rest all parameters will remain the same
so we will have

now from above two equations we have

so new current will become
