Answer:
option (C)
Explanation:
The amount of heat required to raise the temperature of substance of unit mass by unit degree is called specific heat of that substance.
Its SI unit is Joule / Kg °C.
Every material has a constant value of specific heat.
So, option (c) is correct.
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
The box is kept in motion at constant velocity by a force of F=99 N. Constant velocity means there is no acceleration, so the resultant of the forces acting on the box is zero. Apart from the force F pushing the box, there is only another force acting on it in the horizontal direction: the frictional force

which acts in the opposite direction of the motion, so in the opposite direction of F.
Therefore, since the resultant of the two forces must be zero,

so

The frictional force can be rewritten as

where

,

. Re-arranging, we can solve this equation to find

, the coefficient of dynamic friction:
Answer:
option c is correct
Explanation:
we know that time rate of change of velocity is called acceleration
so a=v/t
a=12/4
a=3m/s²
Because they have no opposing fields to cancel their effects, these electrons have an orbital magnetic. Magnetic moments<span> come from the moments of all of its </span>atoms<span>.</span>