Answer:
The correct answer is;
Change of phase.
Explanation:
When the physical state in which a substance exists in nature changes to another physical state such as a change from solid state to a liquid stat or from a liquid state to a gaseous state, the substance is said to have undergone a phase change, or phase transformation.
The state of a substance will change, depending on the surrounding temperature and the applied pressure and the energy required for the substance to change its state is known as latent heat.
The observed plateaus are periods the latent heat is absorbed to completely change the phase of the substance.
 
        
             
        
        
        
Answer:
0.54m
Explanation:
Step one:
given data
length of seesaw= 3m
mass of man m1= 85kg
weight = mg
W1= 85*10= 850N
mass of daughter m2= 35kg
W2= 35*10= 350N
distance from the center= (1.5-0.2)= 1.3m
Step two:
we know that the sum of clockwise moment equals the anticlockwise moment
let the distance the must sit to balance the system be x
taking moment about the center of the system
350*1.3=850*x
455=850x
divide both sides by  850
x=455/850
x=0.54
Hence the man must sit 0.54m from the right to balance the system
 
        
             
        
        
        
Answer:
D. only briefly while being connected or disconnected.
Explanation:
As we know that transformer works on the principle of mutual inductance
here we know that as per the principle of mutual inductance when flux linked with the primary coil charges then it will induce EMF in secondary coil
So here when AC source is connected with primary coil then it will give output across secondary coil because AC source will have change in flux with time.
Now when we connect DC source across primary coil then it will not induce any EMF across secondary coil because DC source is a constant voltage source in which flux will remain constant always
So here in DC source the EMF will only induce at the time of connection or disconnection when flux will change in it while rest of the time it will give ZERO output
so correct answer will be
D. only briefly while being connected or disconnected.
 
        
             
        
        
        
Answer:
If the frequency of the motion of a simple harmonic oscillator is doubled , then maximum speed of the oscillator changes by the factor 2 
Explanation:
We know that in a simple harmonic oscillator the maximum speed is given by 
      =
 = 
   Here A is amplitude which is constant , so from above equation we see that maximum speed is directly proportional to  of the oscillation .
 of the oscillation .
   Since  
        = 2
 = 2 
   Where  is the maximum speed when frequency is doubled .
 is the maximum speed when frequency is doubled .
 
        
             
        
        
        
Answer:
Three types of thermal expansion are linear expansion,s superficial expansion,cubical expansion