1
AIPMT 2015 Cancelled Paper
+4
-1
A wire carrying current $$I$$ has the shape shown in adjoining figure.

Linear parts of the wire are very long and parallel to X-axis while semicircular protion of radius R is lying in Y-Z plane. Magtnetic field at pont $$O$$ is
A
$$\overrightarrow B = - {{{\mu _0}I} \over {4\pi R}}\left( {\pi \widehat i + 2\widehat k} \right)$$
B
$$\overrightarrow B = {{{\mu _0}I} \over {4\pi R}}\left( {\pi \widehat i - 2\widehat k} \right)$$
C
$$\overrightarrow B = {{{\mu _0}I} \over {4\pi R}}\left( {\pi \widehat i + 2\widehat k} \right)$$
D
$$\overrightarrow B = - {{{\mu _0}I} \over {4\pi R}}\left( {\pi \widehat i - 2\widehat k} \right)$$
2
AIPMT 2014
+4
-1
Two identical long conducting wires $$AOB$$ and $$COD$$ are placed at right angle to each other, with one above other such that $$O$$ is their common point for the two. The wires carry $$I$$1 and $$I$$2 currents, respectively. Point $$P$$ is lying at distance f from $$O$$ along a direction perpendicular to the plane containing the wires. The magnetic field at the point $$P$$ will be
A
$${{{\mu _0}} \over {2\pi d}}\left( {{{{I_1}} \over {{I_2}}}} \right)$$
B
$${{{\mu _0}} \over {2\pi d}}\left( {{I_1} + {I_2}} \right)$$
C
$${{{\mu _0}} \over {2\pi d}}\left( {I_1^2 - I_2^2} \right)$$
D
$${{{\mu _0}} \over {2\pi d}}{\left( {I_1^2 + I_2^2} \right)^{1/2}}$$
3
AIPMT 2014
+4
-1
In an ammeter 0.2% of main current passes through the galvanometer. If resistance of galvanometer is G, the resistance of ammeter will be
A
$${1 \over {499}}G$$
B
$${{499} \over {500}}G$$
C
$${1 \over {500}}G$$
D
$${{500} \over {499}}G$$
4
NEET 2013 (Karnataka)
+4
-1
A long straight wire carries a certain current and produces a magnetic field 2 $$\times$$ 10$$-$$4 Wb m$$-$$2 at a perpendicular distance of 5 cm from the wire. An electron situated at 5 cm from the wire moves with a velocity 107 m/s towards the wire along perpendicular to it. The force experienced by the electron will be (charge on electron 1.6 $$\times$$ 10$$-$$19 C)
A
3.2 N
B
3.2 $$\times$$ 10$$-$$16 N
C
1.6 $$\times$$ 10$$-$$16 N
D
zero
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