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An electric field of $1500 \mathrm{~V} / \mathrm{m}$ and a magnetic field of $0.40 \mathrm{~Wb} / \mathrm{m}^{2}$ act on a moving electron. The minimum uniform speed along a straight line the electron could have is
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The correct answer is:
$3.75 \times 10^{3} \mathrm{~m} / \mathrm{s}$
Given, electric field, $E=1500 \mathrm{~V} / \mathrm{m}$
Magnetic field, $B=0.4 \mathrm{~Wb} / \mathrm{m}^{2}$
Charge on electron, $q=e=1.6 \times 10^{-19} \mathrm{C}$
For minimum uniform speed of electron along a straight line is a region, where electric field $E$ and magnetic field $B$, both are present is given as
$v=\frac{E}{B} \quad\left[\begin{array}{l}\because q E=B q v \\ \Rightarrow v=\frac{E}{B}\end{array}\right]$
$=\frac{1500}{0.4}$
$=3750 \mathrm{~m} / \mathrm{s}$
$=3.75 \times 10^{3} \mathrm{~m} / \mathrm{s}$
Magnetic field, $B=0.4 \mathrm{~Wb} / \mathrm{m}^{2}$
Charge on electron, $q=e=1.6 \times 10^{-19} \mathrm{C}$
For minimum uniform speed of electron along a straight line is a region, where electric field $E$ and magnetic field $B$, both are present is given as
$v=\frac{E}{B} \quad\left[\begin{array}{l}\because q E=B q v \\ \Rightarrow v=\frac{E}{B}\end{array}\right]$
$=\frac{1500}{0.4}$
$=3750 \mathrm{~m} / \mathrm{s}$
$=3.75 \times 10^{3} \mathrm{~m} / \mathrm{s}$
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