Answer:
Explanation:
Given that,
Current in loops are
 i1 = 12A
i2 = 20A
The loops are 3.4cm apart 
The magnetic field at the center is found to be zero, so when want to find the radius of bigger loop
Magnetic Field is given as 
B= μoi/2πr
Where,
μo is a constant = 4π×10^-7 Tm/A
r is the distance between the two wires
i is the current in the wires
B is the magnetic field 
NOTE
Field due to large loop should be equal to the smaller loop.
B1 = B2
μo•i1 / 2π•r1 = μo•i2 / 2π•r2
Then, μo, 2π cancels out, so we have
i1 / r1 = i2 / r2
Make r2 subject of formula
i1•r2 = i2•r1
r2 = i2•r1 / i2
r2 = 20×3.4/12
r2 = 5.67cm
The radius of the bigger loop is 5.67cm.
 
        
             
        
        
        
Answer:
Al llegar a su equilibrio térmico ambas barran tendrán una temperatura de 53 grados centígrados.
Explanation:
Dado que una barra de aluminio que está a 78 grados centígrados entra en contacto con una barra de cobre de la misma longitud y área que esta a 28 grados centígrados, y posteriormente se lleva acabo la transferencia de energía entre ambas barras llegando a su equilibrio térmico, para determinar la temperatura a la que ambas barras llegarán se debe realizar el siguiente cálculo: 
(78 + 28) / 2 = X
106 / 2 = X
53 = X
Por lo tanto, al llegar a su equilibrio térmico ambas barran tendrán una temperatura de 53 grados centígrados.
 
        
             
        
        
        
MARK ME BRAINLIEST!! 
your answer should be “C”.
        
             
        
        
        
False the North Star never changes it position
        
             
        
        
        
Explanation:
1. Phases of Venus: Galileo was the first astronomer to use a telescope to observe the celestial objects. Through a telescope he observed that Venus shows the phases just like the Moon. This proved the Heliocentric theory correct against the then prevalent Geocentric theory.
2. Law of Falling bodies: The acceleration due to gravity is independent of weight of the objects that means two bodies of different mass will hit the ground at the same time if dropped from the same height.
3. The uneven surface of the Moon: He observed that the surface of the Moon is uneven and rough.
4. Discovery of the 4 Moons of Jupiter