1
NEET 2016 Phase 2
+4
-1
A filament bulb (500 W, 100 V) is to be used in a 230 V main supply. When a resistance R is connected in series, it works perfectly and the bulb consumes 500 W. The value of R is
A
230 $$\Omega$$
B
46 $$\Omega$$
C
26 $$\Omega$$
D
13 $$\Omega$$
2
NEET 2016 Phase 1
+4
-1
A potentiometer wire is 100 cm long and a constant potential difference is maintained across it. Two cells are connected in series first to support one another and then in opposite direction. The balance points are obtained at 50 cm and 10 cm from the positive end of the wire in the two cases. The ratio of emf's is
A
3 : 4
B
3 : 2
C
5 : 1
D
5 : 4
3
NEET 2016 Phase 1
+4
-1
The charge flowing through a resistance R varies with time t is Q = at $$-$$ bt2, where $$a$$ and $$b$$ are positive constants. The total heat produced in R is
A
$${{{a^3}R} \over {2b}}$$
B
$${{{a^3}R} \over {b}}$$
C
$${{{a^3}R} \over {6b}}$$
D
$${{{a^3}R} \over {3b}}$$
4
AIPMT 2015
+4
-1
Two metal wires of identical dimensions are connected in series. If $$\sigma$$1 and $$\sigma$$2 are the conductivity of the combination is
A
$${{{\sigma _1} + {\sigma _2}} \over {{\sigma _1}{\sigma _2}}}$$
B
$${{{\sigma _1}{\sigma _2}} \over {{\sigma _1} + {\sigma _2}}}$$
C
$${{2{\sigma _1}{\sigma _2}} \over {{\sigma _1} + {\sigma _2}}}$$
D
$${{{\sigma _1} + {\sigma _2}} \over {2{\sigma _1}{\sigma _2}}}$$
EXAM MAP
Medical
NEET