1
AIEEE 2003
+4
-1
The length of a given cylindrical wire is increased by $$100\%$$. Due to the consequent decrease in diameter the change in the resistance of the wire will be
A
$$200\%$$
B
$$100\%$$
C
$$50\%$$
D
$$300\%$$
2
AIEEE 2003
+4
-1
Out of Syllabus
The length of a wire of a potentiometer is $$100$$ $$cm$$, and the $$e.$$ $$m.$$ $$f.$$ of its standard cell is $$E$$ volt. It is employed to measure the $$e.m.f.$$ of a battery whose internal resistance in $$0.5\Omega .$$ If the balance point is obtained at $$1=30$$ $$cm$$ from the positive end, the $$e.m.f.$$ of the battery is

where $$i$$ is the current in the potentiometer wire.

A
$${{30E} \over {100.5}}$$
B
$${{30E} \over {\left( {100 - 0.5} \right)}}$$
C
$${{30\left( {E - 0.5i} \right)} \over {100}}$$
D
$${{30E} \over {100}} - 0.5i$$, where i is the current in the potentiometer wire
3
AIEEE 2003
+4
-1
The thermo $$e.m.f.$$ of a thermo -couple is $$25$$ $$\mu V/{}^ \circ C$$ at room temperature. A galvanometer of $$40$$ $$ohm$$ resistance, capable of detecting current as low as $${10^{ - 5}}\,A,$$ is connected with the thermo couple. The smallest temperature difference that can be detected by this system is
A
$${16^0}C$$
B
$${12^0}C$$
C
$${8^0}C$$
D
$${20^0}C$$
4
AIEEE 2003
+4
-1
An ammeter reads upto $$1$$ ampere. Its internal resistance is $$0.81$$ $$ohm$$. To increase the range to $$10$$ $$A$$ the value of the required shunt is
A
$$0.03\,\Omega$$
B
$$0.3\,\Omega$$
C
$$0.9\,\Omega$$
D
$$0.09\,\Omega$$
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