Answer:
E. Some charges in the region are positive, and some are negative.
Explanation:
Electric potential is given as;

where;
W is the work done in moving a charge between two points which have a difference in potential
Q is quantity of charge in the given region
If the electric potential at a given point in the region is zero, then sum of the charges in the given region must be equal to zero. For the charges to sum to zero, some will be positive while some will be negative,.
Therefore, the correct statement in the given options is "E"
E. Some charges in the region are positive, and some are negative.
<em>500 sec</em>
<em>8 min 20 sec</em>
<em>Hi there !</em>
<em />
<em>8 m ................ 1 s </em>
<em>4000 m ........ x s</em>
<em>x = 4000m×1s/8m = 500 sec = 8 min 20 sec</em>
<em />
<em>Good luck ! </em>
Answer:
a) 
b) 
Explanation:
given,
n =1.5 for glass surface
n = 1 for air
incidence angle = 45°
using Fresnel equation of reflectivity of S and P polarized light

using snell's law to calculate θ t


a) 

b) 

Answer:
the heat absorbed by the block of copper is 74368.476J
Explanation:
Hello!
To solve this problem use the first law of thermodynamics that states that the heat applied to a system is the difference between the initial and final energy considering that the mass and the specific heat do not change so we can infer the following equation
Q=mCp(T2-T1)
Where
Q=heat
m=mass=2.3kg
Cp=0.092 kcal/(kg C)=384.93J/kgK
T2=Final temperatura= 90C
T1= initial temperature=6 C
solving

the heat absorbed by the block of copper is 74368.476J
The Earth is a sphere is a statement to describe a scientific law