I believe the answer is B, a real and inverted image is formed on the side of the lens opposite the rubber ducky. The focal length is 15 cm and therefore the center of curvature (2F) will be 30 cm. When the object is placed between F and 2F (in this case 20 cm) in front of a convex lens, an inverted, real image is formed on the other side of the lens.
Answer:
E/4
Explanation:
The formula for electric field of a very large (essentially infinitely large) plane of charge is given by:
E = σ/(2ε₀)
Where;
E is the electric field
σ is the surface charge density
ε₀ is the electric constant.
Formula to calculate σ is;
σ = Q/A
Where;
Q is the total charge of the sheet
A is the sheet's area.
We are told the elastic sheet is a square with a side length as d, thus ;
A = d²
So;
σ = Q/d²
Putting Q/d² for σ in the electric field equation to obtain;
E = Q/(2ε₀d²)
Now, we can see that E is inversely proportional to the square of d i.e.
E ∝ 1/d²
The electric field at P has some magnitude E. We now double the side length of the sheet to 2L while keeping the same amount of charge Q distributed over the sheet.
From the relationship of E with d, the magnitude of electric field at P will now have a quarter of its original magnitude which is;
E_new = E/4
Average speed = (total distance covered) / (time to cover the distance)
-- Traveling at 40 mph for 1 hour, the distance covered is 40 miles.
-- Traveling at 60 mph for 1 hour, the distance covered is 60 miles.
-- Total distance covered = (40 miles) + (60 miles) = 100 miles
-- Total time = (1 hour) + (1 hour) = 2 hours
-- Average speed = (100 miles) / (2 hours)
<em>Average speed = 50 miles per hour</em>
Think about how each of noise, heat, visible light, radiation and atmospheric shock waves travel. Which ones require air particles to travel?
A vacuum has no air particles within it, it is completely empty.
Therefore, any of the above that requiring particles to travel will not be able to cross it and the observer will not experience it.
