Answer
Verified
38.7k+ views
Hint: In order to solve this question, we will first check the correctness of both the given assertion and reason statements and then we will check whether the reason is the correct explanation of assertion or not.
Formula used:
The expression of Lorentz force is given as,
$F = q(v \times B)$ Here, $q$ is the charge on the particle, $v$ is the velocity of the charged particle and $B$ is the magnetic field.
Complete step by step solution:
We have given the assertion statement as An electron is not deflected on passing through a certain region of space. This observation confirms that there is no magnetic field in that region, so when an electric charge enters a field and if it’s not deflected it does not confirm that there is no magnetic field because if the velocity of the particle is parallel to the magnetic field then Lorentz force on the particle is
$F = q(v \times B) \\
\Rightarrow F = qvB\sin \theta $
As the velocity of the particle is parallel to the magnetic field therefore $\sin \theta =0$.
$\Rightarrow F = 0 $
Since, the angle between velocity and the magnetic field is zero, so our assertion is false.
Now, the reason statement is given to us that The deflection of an electron depends on the angle between the velocity of the electron and the direction of the magnetic field and yes, the reason is true as the deflection of an electron depends upon the angle between velocity and magnetic field as we have written in Lorentz force as $F = q(v \times B)$. But, the reason statement does not say how the deflection depends upon the angle so the reason is correct but it does not explain our assertion.
Hence, the correct answer is option D.
Note:It should be remembered that in the formula of Lorentz for velocity v and magnetic field B are used in vector form and the product between them is vector product also, remember the trigonometric values as $\sin {0^o} = 0.$
Formula used:
The expression of Lorentz force is given as,
$F = q(v \times B)$ Here, $q$ is the charge on the particle, $v$ is the velocity of the charged particle and $B$ is the magnetic field.
Complete step by step solution:
We have given the assertion statement as An electron is not deflected on passing through a certain region of space. This observation confirms that there is no magnetic field in that region, so when an electric charge enters a field and if it’s not deflected it does not confirm that there is no magnetic field because if the velocity of the particle is parallel to the magnetic field then Lorentz force on the particle is
$F = q(v \times B) \\
\Rightarrow F = qvB\sin \theta $
As the velocity of the particle is parallel to the magnetic field therefore $\sin \theta =0$.
$\Rightarrow F = 0 $
Since, the angle between velocity and the magnetic field is zero, so our assertion is false.
Now, the reason statement is given to us that The deflection of an electron depends on the angle between the velocity of the electron and the direction of the magnetic field and yes, the reason is true as the deflection of an electron depends upon the angle between velocity and magnetic field as we have written in Lorentz force as $F = q(v \times B)$. But, the reason statement does not say how the deflection depends upon the angle so the reason is correct but it does not explain our assertion.
Hence, the correct answer is option D.
Note:It should be remembered that in the formula of Lorentz for velocity v and magnetic field B are used in vector form and the product between them is vector product also, remember the trigonometric values as $\sin {0^o} = 0.$
Recently Updated Pages
silver wire has diameter 04mm and resistivity 16 times class 12 physics JEE_Main
A parallel plate capacitor has a capacitance C When class 12 physics JEE_Main
Let gx 1 + x x and fx left beginarray20c 1x 0 0x 0 class 12 maths JEE_Main
A series combination of n1 capacitors each of value class 12 physics JEE_Main
When propyne is treated with aqueous H2SO4 in presence class 12 chemistry JEE_Main
Which of the following is not true in the case of motion class 12 physics JEE_Main
Other Pages
Oxidation state of S in H2S2O8 is A 6 B 7 C +8 D 0 class 12 chemistry JEE_Main
Excluding stoppages the speed of a bus is 54 kmph and class 11 maths JEE_Main
Differentiate between homogeneous and heterogeneous class 12 chemistry JEE_Main
What is the volume of water that must be added to a class 11 chemistry JEE_Main
when an object Is placed at a distance of 60 cm from class 12 physics JEE_Main
If a wire of resistance R is stretched to double of class 12 physics JEE_Main