Answer:
Part a)

Part b)

Explanation:
Part a)
Electric field due to large sheet is given as







now the electric field is given as


Part b)
Now since the electric field is required at same distance on other side
so the field will remain same on other side of the plate

Convection means that hotter and less dense fluids have a tendency to rise while colder and more dense fluids sink.
The answer would be (A)
Hot water is denser than cold water and so hot water will be above the cold water.
:D
Answer:
No. of laps of Hannah are 7 (approx).
Solution:
According to the question:
The total distance to be covered, D = 5000 m
The distance for each lap, x = 400 m
Time taken by Kara, 
Time taken by Hannah, 
Now, the speed of Kara and Hannah can be calculated respectively as:


Time taken in each lap is given by:



t = 500 s
So, Distance covered by Hannah in 't' sec is given by:


No. of laps taken by Hannah when she passes Kara:

≈ 7 laps
To answer the problem we would be using this formula which isE = hc/L where E is the energy, h is Planck's constant, c is the speed of light and L is the wavelength
L = hc/E = 4.136×10−15 eV·s (2.998x10^8 m/s)/10^4 eV
= 1.240x10^-10 m
= 1.240x10^-1 nm