1
JEE Main 2015 (Offline)
MCQ (Single Correct Answer)
+4
-1
Change Language
Two long current carrying thin wires, both with current $$I,$$ are held by insulating threads of length $$L$$ and are in equilibrium as shown in the figure, with threads making an angle $$'\theta '$$ with the vertical. If wires have mass $$\lambda $$ per unit-length then the value of $$I$$ is :
($$g=$$ $$gravitational$$ $$acceleration$$ )

JEE Main 2015 (Offline) Physics - Magnetic Effect of Current Question 190 English
A
$$2\sqrt {{{\pi gL} \over {{\mu _0}}}\tan \theta } $$
B
$$\sqrt {{{\pi \lambda gL} \over {{\mu _0}}}\tan \theta } $$
C
$$\sin \theta \sqrt {{{\pi \lambda gL} \over {{\mu _0}\,\cos \theta }}} $$
D
$$2\sin \theta \sqrt {{{\pi \lambda gL} \over {{\mu _0}\,\cos \theta }}} $$
2
JEE Main 2015 (Offline)
MCQ (Single Correct Answer)
+4
-1
Change Language
When $$5V$$ potential difference is applied across a wire of length $$0.1$$ $$m,$$ the drift speed of electrons is $$2.5 \times {10^{ - 4}}\,\,m{s^{ - 1}}.$$ If the electron density in the wire is $$8 \times {10^{28}}\,\,{m^{ - 3}},$$ the resistivity of the material is close to :
A
$$1.6 \times {10^{ - 6}}\Omega m$$
B
$$1.6 \times {10^{ - 5}}\Omega m$$
C
$$1.6 \times {10^{ - 8}}\Omega m$$
D
$$1.6 \times {10^{ - 7}}\Omega m$$
3
JEE Main 2015 (Offline)
MCQ (Single Correct Answer)
+4
-1
Change Language
A long cylindrical shell carries positives surfaces change $$\sigma $$ in the upper half and negative surface charge - $$\sigma $$ in the lower half. The electric field lines around the cylinder will look like figure given in :
(figures are schematic and not drawn to scale)
A
JEE Main 2015 (Offline) Physics - Electrostatics Question 219 English Option 1
B
JEE Main 2015 (Offline) Physics - Electrostatics Question 219 English Option 2
C
JEE Main 2015 (Offline) Physics - Electrostatics Question 219 English Option 3
D
JEE Main 2015 (Offline) Physics - Electrostatics Question 219 English Option 4
4
JEE Main 2015 (Offline)
MCQ (More than One Correct Answer)
+4
-1
Change Language
A uniformly charged solid sphere of radius $$R$$ has potential $${V_0}$$ (measured with respect to $$\infty $$) on its surface. For this sphere the equipotential surfaces with potentials $${{3{V_0}} \over 2},\,{{5{V_0}} \over 4},\,{{3{V_0}} \over 4}$$ and $${{{V_0}} \over 4}$$ have radius $${R_1},\,\,{R_2},\,\,{R_3}$$ and $${R_4}$$ respectively. Then
A
$${R_1} = 0$$ and $${R_2} < \left( {{R_4} - {R_3}} \right)$$
B
$$2R < {R_4}$$
C
$${R_1} = 0$$ and $${R_2} > \left( {{R_4} - {R_3}} \right)$$
D
$${R_1} \ne 0$$ and $$\left( {{R_2} - {R_1}} \right) > \left( {{R_4} - {R_3}} \right)$$
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