JEE MAIN - Physics (2023 - 11th April Evening Shift - No. 15)
When vector $$\vec{A}=2 \hat{i}+3 \hat{j}+2 \hat{k}$$ is subtracted from vector $$\overrightarrow{\mathrm{B}}$$, it gives a vector
equal to $$2 \hat{j}$$. Then the magnitude of vector $$\overrightarrow{\mathrm{B}}$$ will be :
3
$$\sqrt{33}$$
$$\sqrt6$$
$$\sqrt5$$
Explanation
Given that when vector $$\vec{A}=2 \hat{i}+3 \hat{j}+2 \hat{k}$$ is subtracted from vector $$\overrightarrow{\mathrm{B}}$$, it gives a vector equal to $$2 \hat{j}$$.
We can write this as:
$$\vec{B} - \vec{A} = 2 \hat{j}$$
Now, let's express the vector $$\overrightarrow{\mathrm{B}}$$ in terms of its components:
$$\vec{B} = B_x \hat{i} + B_y \hat{j} + B_z \hat{k}$$
Subtract vector $$\vec{A}$$ from vector $$\vec{B}$$:
$$(B_x \hat{i} + B_y \hat{j} + B_z \hat{k}) - (2 \hat{i}+3 \hat{j}+2 \hat{k}) = 2 \hat{j}$$
Comparing the components, we get:
$$ B_x - 2 = 0 \\ B_y - 3 = 2 \\ B_z - 2 = 0 $$
Solving these equations, we find the components of vector $$\vec{B}$$:
$$ B_x = 2 \\ B_y = 5 \\ B_z = 2 $$
Now, we can find the magnitude of vector $$\vec{B}$$:
$$ |\vec{B}| = \sqrt{B_x^2 + B_y^2 + B_z^2} = \sqrt{2^2 + 5^2 + 2^2} = \sqrt{4 + 25 + 4} = \sqrt{33} $$
Therefore, the magnitude of vector $$\overrightarrow{\mathrm{B}}$$ is $$\sqrt{33}$$
We can write this as:
$$\vec{B} - \vec{A} = 2 \hat{j}$$
Now, let's express the vector $$\overrightarrow{\mathrm{B}}$$ in terms of its components:
$$\vec{B} = B_x \hat{i} + B_y \hat{j} + B_z \hat{k}$$
Subtract vector $$\vec{A}$$ from vector $$\vec{B}$$:
$$(B_x \hat{i} + B_y \hat{j} + B_z \hat{k}) - (2 \hat{i}+3 \hat{j}+2 \hat{k}) = 2 \hat{j}$$
Comparing the components, we get:
$$ B_x - 2 = 0 \\ B_y - 3 = 2 \\ B_z - 2 = 0 $$
Solving these equations, we find the components of vector $$\vec{B}$$:
$$ B_x = 2 \\ B_y = 5 \\ B_z = 2 $$
Now, we can find the magnitude of vector $$\vec{B}$$:
$$ |\vec{B}| = \sqrt{B_x^2 + B_y^2 + B_z^2} = \sqrt{2^2 + 5^2 + 2^2} = \sqrt{4 + 25 + 4} = \sqrt{33} $$
Therefore, the magnitude of vector $$\overrightarrow{\mathrm{B}}$$ is $$\sqrt{33}$$
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