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Physics 1 Marks Question

Electric Charges and Fields · CBSE STD 12 Science (CBSE - English Medium). 62 questions.

Questions · Page 2 of 2

1 Marks Question

Question 511 Mark
Write the formula of Coulomb's law in vacuum or air.
Answer
$\overrightarrow{ F _{12}}=\frac{1}{4 \pi \epsilon_0} \frac{q_1 q_2}{r_{12}^2} r_{12}^{\prime}$
where $\frac{1}{4 \pi \epsilon_0}=9 \times 10^9 Nm ^2 / C ^2$
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Question 521 Mark
One Coulomb charge is equal to how many electrons?
Answer
$n=\frac{q}{e}=\frac{1}{1.6 \times 10^{-19}}=6.25 \times 10^{18}$
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Question 531 Mark
Will a charged body attract a nearby uncharged body?
Answer
Yes, a charged body, by induction, produces a charge of opposite nature on the nearby surface of the un- charged body and of the same nature on the distant surface, due to which a net attractive force starts appearing between them.
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Question 541 Mark
Define the S.1. unit of electric charge (coulomb).
Answer
One Coulomb charge is a charge which, if kept at a distance of 1 meter from itself in air or vacuum, repels its similar charge with a force of $9 \times 10^9$ Newton.
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Question 571 Mark
Which forces does a stationary charge produce? If the charge moves with uniform velocity then?
Answer
Stationary charge produces only electric field. A charge moving with uniform velocity produces both electric and magnetic fiels.
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Question 581 Mark
In which activities does the law of conservation of charge apply?
Answer
(i) In nuclear reactions (ii) In pair production process (iii) In friction process.
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Question 591 Mark
What does $q_1+q_2=0$ represent in electrostatics?
Answer
$q_1+q_2=0 \Rightarrow q_1=-q_2 i$ e. $q_1$ and $q_2$ are equal in result and opposite in nature. In electronics it actually refers to charge conservation.
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Question 601 Mark
$q_1$ and $q_2$ are point charges such that $q_1 \times q_2>9$. What is the nature of the force between the two charges?
Answer
Here, $q_1 q_2>0$. This means that $q_1>0$ and $q_2>0$ or $q_1<0, q_2<0$ when both $q_1$ and $q_2$ are positive or negative. Thus, the foree between $q_1$ and $q_2$ will be repulsive.
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Question 611 Mark
Two electrons are kept at a distance of I A from cach other. Calculate the Coulomb force between them.
Answer
$F =\frac{1}{4 \pi \epsilon_0} \times \frac{q_1 q_2}{r^2}$
$=9 \times 10^9 \times \frac{\left(1.6 \times 10^{-19}\right)^2}{\left(10^{-10}\right)^2}$
$=2.3 \times 10^{-8} N$
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Question 621 Mark
What does it mean for an object to be positively and negatively charged?
Answer
Compared to the normal state, the lack of electrons in an object shows that it is positively charged and the excess of electrons shows that it is negatively charged.
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1 Marks Question - Page 2 - Physics STD 12 Science Questions - Vidyadip