The force that opposes relative motion between surfaces in contact is
A. Gravitational force
B. Frictional force
C. Electrostatic force
D. Magnetic force
Answer: Option B
Solution (By JKSSB Mock Tests)
Friction acts parallel to surfaces, opposes motion. Static, kinetic, rolling friction. Depends on normal force and surface roughness. Necessary for walking, vehicles.
Explanation:
An alpha particle consists of two protons and two neutrons tightly bound together. This is completely identical to the nucleus of a helium atom (He²⁺). Alpha particles are positively charged, relatively massive, have low penetrating power, and are emitted by heavy radioactive elements during alpha decay.
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