Answer:
0
Explanation:
The overall charge on this atom is 0. 
   To find the charge on an atom; 
            charge  = number of protons - number of electrons. 
Note: 
- Protons are the positively charged particles in an atom
 - Electrons are the negatively charged particles in an atom
 - Neutrons carries no charges on them. 
 
Since the atom is made up of equal number of protons and electrons, the charge on it is 0. 
If the number of electrons is more, the atom will be negatively charge but if the number of protons is more, it will be positively charged. 
 
        
                    
             
        
        
        
Answer:
Explanation:
Given
Lowest four resonance frequencies are given with magnitude 
50,100,150 and 200 Hz
The frequency of vibrating string is given by 

where n=1,2,3 or ...n
L=Length of string
T=Tension
Mass per unit length 
When string is clamped at mid-point
Effecting length becomes 
Thus new Frequency becomes 

i.e. New frequency is double of old
so new lowest four resonant frequencies are 100,200,300 and 400 Hz      
 
        
             
        
        
        
Answer:
4 m/s
Explanation:
m1 = m2 = m 
u1 = 20 m/s, u2 = - 12 m/s
Let the speed of composite body is v after the collision. 
Use the conservation of momentum 
Momentum before collision = momentum after collision
m1 x u1 + m2 x u2 = (m1 + m2) x v 
m x 20 - m x 12 = (m + m) x v 
20 - 12 = 2 v 
8 = 2 v 
v = 4 m/s 
Thus, the speed of teh composite body is 4 m/s.
 
        
             
        
        
        
Answer:
 induced electromotive force (Voltage)    E = - N dΦ / dt
Explanation:
When the magnetic flux this coil induces a current in each turn of the coil, which is why an induced electromotive force (Voltage) appears at the ends of the coil.
This phenomenon is fully explained by Faraday's law
         E = - dΦ / dt
where in the case of a coil with N turns of has
         E = - N dΦ / dt
Rl flux is the product of the normal to the area by the magnetic field, in this case the flux changes so we can assume that the area of the coil is constant