It’s D. An enlargement (hope this helps!)
Answer:

Explanation:
Here two charges are placed at distance "d" apart
now the net value of electric field at some position between two charges will be ZERO
so we will have
electric field due to charge 1 = electric field due to charge 2

Let the position where net field is zero will lie at distance "r" from q1

now we will have

now square root both sides

now we have

so we have

Answer:
Explanation:
Given
Distance between two loud speakers 
Distance of person from one speaker 
Distance of person from second speaker 
Path difference between the waves is given by

for destructive interference m=0 I.e.




frequency is given by

where 

For next frequency which will cause destructive interference is
i.e.
and 


frequency corresponding to this is

for 


Frequency corresponding to this wavelength

Formulas change from F to degree C : C = ( F - 32 )/1.8
so we have (77-32)/1.8 = 25 oC
ok done. Thank to me :>
Answer:33
Explanation:
F = frequency
N = Node count
w = wave lenght
v = wave velocity
L = distance wave traveled
First find wave length of laser
w = (2/(N))*(L)
w = (2/(10))*(8)
w = 1.6
then using (w), find velocity
V = (w)(F)
V = (1.6)*(108)
V = 288
Plug in V and the new frequency to solve for new node count
F = NV/2L
(600) = (N)*(288) / 2 * (8)
(N) = 33.33
there are 33 nodes