Answer:

Explanation:
a. The wire's length is 10m long and has a mass 100g and a tension of 250N.
Frequency is given by the equation:
#where t=250N*10=2500N, 
#substitute for actual values for the lowest frequency.
#n=1, lowest frequency
Hence, the lowest frequency for standing waves is 7.9057Hz
b.The wire's length is 10m long and has a mass 100g and a tension of 250N.
Frequency is given by the equation:
#where t=250N*10=2500N,
#The second lowest frequency happens at
:

Hence, the second lowest frequency is 15.8114Hz
c.Given that the wire's length is 10m long and has a mass 100g and a tension of 250N.
Frequency is given by the equation:
#where t=250N*10=2500N,
The third lowest frequency happens at 

Hence, the third lowest frequency is 23.7171Hz
Answer:
We know that force applied per unit area is called pressure.
Pressure = Force/ Area
When force is constant than pressure is inversely proportional to area.
1- Calculating the area of three face:
A1 = 20m x 10 m =200 Square meter
A2 = 10 mx 5 m = 50 Square meter
A3 = 20m x 5 m = 100 Square meter
Therefore A1 is maximum and A2 is minimum.
2- Calculate pressure:
P = F/ A1 = 30 / 200 = 0.15 Nm⁻² ( minimum pressure)
P = F / A2 = 30 / 50 = 0.6 Nm⁻² ( maximum pressure)
Hence greater the area less will be the pressure and vice versa.
The answer is (a) because movement is acceleration
Answer:
a ) 1.267 radian
b ) 1.084 10⁻³ mm
Explanation:
Distance of screen D = 1.65 m
Width of slit d = ?
Wave length of light λ = 687 nm.
Distance of second minimum fro centre y = 2.09 cm
Angle of diffraction = y / D
= 2.09 /1.65
= 1.267. radian
Angle of diffraction of second minimum
= 2 λ / d
so 2 λ / d = 1.267
d = 2 λ / 1.267 = (2 x 687 ) /1.267 nm
=1084.45 nm = 1.084 x 10⁻³ mm.