The specific charge (e/m) of an electron was first measured by:
A. Rutherford
B. Millikan
C. Bohr
D. Thomson
Answer: Option D
Solution (By JKSSB Mock Tests)
J. J. Thomson measured the specific charge (e/m) of electrons in 1897 using cathode ray tube experiments with electric and magnetic fields. Millikan later measured the charge e (oil drop experiment), allowing mass calculation. Rutherford discovered nucleus; Bohr developed atomic model. Memory aid: 'Thomson = e/m; Millikan = e'. This history-based question tests knowledge of experimental physics milestones, frequently appearing in competitive exams. Always link scientists to their specific measurements: Thomson (e/m), Millikan (e), Chadwick (neutron).
Explanation:
In solids, heat flows by conduction (lattice vibrations and free electrons). Metals are good conductors due to free electrons. Convection in fluids, radiation no medium.
Explanation:
Electric potential V at a point is defined as work done per unit charge to bring a test charge from infinity to that point: V = W/q. Thus potential difference between two points is work per unit charge to move between them. Electric field intensity is force per unit charge; potential energy is work to assemble charges; capacitance is charge storage ability. Memory tip: 'Potential = work per unit charge; field = force per unit charge'. This definition-based question tests electrostatics fundamentals, frequently appearing in competitive exams. Always distinguish potential (scalar, work/charge) from field (vector, force/charge).
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