Answer:
option A
Explanation:
The correct answer is option A
The binary star system is the system in which two stars are continuously orbiting each other,
In the eclipsing binary system, two stars revolve about there center of mass and in this system one one-star eclipse another star.
Spectroscopic binary stars are found from the observation of radial velocity and the brighter member of such binary can be seen to have continuously changed the wavelength and periodic velocity.
When the pairs of stars appear to change position in the sky then it is known as visual binary.
Answer:
(a) Energy density will be equal to 
(b) Total energy will be equal to 0.0718 J
Explanation:
It is given that length of solenoid l = 78.8 cm = 0.788 m
Cross sectional area 
Number of turns of the wire N = 914
Current in the solenoid i = 8.25 A
Inductance of the wire is equal to 
(b) Total energy stored in magnetic field 
(a) Energy density will be equal to
Considering conservation of momentum;
m1v1 + m2v2 = m3v3
In which,
m1 = mass of snowball 1 = 0.4 kg
v1 = velocity of snowball 1 = 15 m/s
m2 = mass of snowball 2 = 0.6 kg
v2 = velocity of snow ball 2 = 15 m/s
m3 = combined mass = 1 kg
v3 = velocity after comination
Therefore;
0.4*15 + 0.6*15 = 1*v3
v3 = 6+9 = 15 m/s
KE = 1/2mv^2
Then,
KE1 = 1/2*0.4*15^2 = 45 J
KE2 = 1/2*0.6*15^2 = 67.5 J
KE3 = 1/2*1*15^2 = 112.5 J
Therefore, KE3 (kinetic energy after collision) = K1+K2 {kinetic energy before collision). And thus it is 100%.
Diffraction means spreading out of waves that has the same wavelength as the size of the gap. Sound waves have high wavelength and so it diffracts\spreads out and enables anyone to hear your voice from anywhere outside the room.
For inside the room, the sound waves doesn't actually diffract. They collide with the air particles, causing a series of compressions and rarefactions which spreads out in the air particles and anyone can hear your voice.
Air is the medium for the sound waves to travel.
Answer:
a) 3.9s
b)74m
Explanation:
a) v=u+at
0=38+(-9.8)t
-38=-9.8t
t=-38/-9.8
t=3.877s
t=3.9s
b) s=ut+1/2at²
s=(38×3.9)+1/2(-9.8×3.9²)
s=148.2 -74.529
s=73.671
s=74m
