"Voltage" is the "pressure" that makes electrons want to leave where they are
and head in some direction, if there's conducting material in that direction.
"Current" is the rate at which they all migrate in that direction.
We have here what is known as parallel combination of resistors.
Using the relation:

And then we can turn take the inverse to get the effective resistance.
Where r is the magnitude of the resistance offered by each resistor.
In this case we have,
(every term has an mho in the end)

To ger effective resistance take the inverse:
we get,

The potential difference is of 9V.
So the current flowing using ohm's law,
V = IR
will be, 0.0139 Amperes.
Number 5 is A
number 6 is D
A joule is a unit of energy.
Answer:
width of slit(a)≅ 0.1mm
Explanation:
Wave length of laser pointer =λ = 685 nm
Distance between screen and slit = L = 5.5 m
Width of bright band = W=8.0cm=0.08m
width of slit=a
recall the formula;
W=(2λL)/a
a=2λL/W
a=(2 *685*10⁻⁹*5.5m)/0.08m
a=7535*10⁻⁹/0.08
a=94187.5 *10⁻⁹
a=0.0000941875m
a=0.0941875mm
a≅0.1mm