A transformer has 100 turns in the primary coil and 500 turns in the secondary coil. If the primary voltage is 220V, what is the secondary voltage assuming 100% efficiency?
A44 V
B220 V
C1100 V
D2200 V
Correct Answer:
C. 1100 V
Explanation:
Using transformer equation: Vₛ/Vₚ = Nₛ/Nₚ. Vₛ = 220 × (500/100) = 220 × 5 = 1100 V.
AAn alpha particle is a helium nucleus with 2 protons and 2 neutrons
BAlpha decay increases the atomic number
CAlpha particles have high penetration power
DAlpha decay produces beta particles
Correct Answer:
A. An alpha particle is a helium nucleus with 2 protons and 2 neutrons
Explanation:
An alpha particle is a helium-4 nucleus (₂He⁴) with 2 protons and 2 neutrons. Alpha decay decreases atomic number by 2 and mass number by 4. Alpha particles have low penetration power.
Which phenomenon explains the blue color of the sky?
ATotal internal reflection
BRayleigh scattering
CMie scattering
DInterference
Correct Answer:
B. Rayleigh scattering
Explanation:
Rayleigh scattering causes shorter blue wavelengths to scatter more effectively than longer red wavelengths when sunlight passes through the atmosphere, making the sky appear blue.
A concave mirror has a focal length of 10 cm. An object is placed 5 cm from the mirror. What type of image is formed?
AReal, inverted, magnified
BVirtual, erect, magnified
CReal, inverted, diminished
DVirtual, erect, diminished
Correct Answer:
B. Virtual, erect, magnified
Explanation:
When object distance (5 cm) < focal length (10 cm), the object is between the mirror and focus. A concave mirror forms a virtual, erect, and magnified image in this case.
