Beta rays emitted by radioactive substances are essentially: MCQ with Answer and Explanation

Beta rays emitted by radioactive substances are essentially:
A. High-speed electrons
B. Helium nuclei
C. Neutrons
D. Electromagnetic waves
Answer: Option A
Solution (By JKSSB Mock Tests)
During beta decay, a neutron in an unstable nucleus transforms into a proton and an electron. The proton remains in the nucleus, but the electron is ejected at high speed. These ejected, high-energy electrons are called beta rays (or beta particles). Gamma rays are electromagnetic waves, and alpha particles are helium nuclei.

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Practice More Physics Questions

Question #1
Escape velocity of a body from Earth is 11.2 km/s. For a planet with mass 9 times Earth and radius same, escape velocity is
A. 3.73 km/s
B. 11.2 km/s
C. 33.6 km/s
D. 22.4 km/s

Correct Answer: Option C


Explanation:
v_esc ∝ √M. M'=9M => v'=3×11.2=33.6 km/s.

This question belongs to: Science Physics
Question #2
The heating element of an electric heater is made of nichrome because it has
A. High resistivity and high melting point
B. Low resistivity and high melting point
C. High resistivity and low melting point
D. Low resistivity and low melting point

Correct Answer: Option A


Explanation:
High resistivity for heat generation; high melting point to withstand high temperature without melting.

This question belongs to: Science Physics
Question #3
A 6 V battery is connected to a 3 Ω resistor. Current is
A. 0.5 A
B. 18 A
C. 2 A
D. 3 A

Correct Answer: Option C


Explanation:
I = V/R = 6/3 = 2 A.

This question belongs to: Science Physics