JEE Main 2016 (Online) 10th April Morning Slot | Current Electricity Question 221 | Physics

JEE Main 2016 (Online) 10th April Morning Slot

MCQ (Single Correct Answer)

-1

The resistance of an electrical toaster has a temperature dependence given by R(T) = R₀ [1 + $$\alpha $$(T − T₀)] in its range of operation. At T₀ = 300 K, R = 100 $$\Omega $$ and at T = 500 K, R = 120 $$\Omega $$. The toaster is connected to a voltage source at 200 V and its temperature is raised at a constant rate from 300 to 500 K in 30 s. The total work done in raising the temperature is :

400 $$\ln \,{{1.5} \over {1.3}}\,J$$

200 $$\ln \,{{2} \over {3}}\,J$$

60000 $$\ln \,{{6} \over {5}}\,J$$

300 J

JEE Main 2016 (Online) 9th April Morning Slot

MCQ (Single Correct Answer)

-1

JEE Main 2016 (Online) 9th April Morning Slot Physics - Current Electricity Question 205 English

In the circuit shown, the resistance r is a variable resistance. If for r = fR, the heat generation in r is maximum then the value of f is :

$${1 \over 4}$$

$${1 \over 2}$$

$${3 \over 4}$$

JEE Main 2016 (Offline)

MCQ (Single Correct Answer)

-1

The temperature dependence of resistance of $$Cu$$ and undoped $$Si$$ in the temperature range $$300-400$$ $$K,$$ is best described by :

Linear increases for $$Cu,$$ exponential decrease of $$Si.$$

Linear decrease for $$Cu,$$ linear decrease for $$Si$$

Linear increase for $$Cu,$$ linear increase for $$Si.$$

Linear increase for $$Cu,$$ exponential increase for $$Si$$

JEE Main 2015 (Offline)

MCQ (Single Correct Answer)

-1

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 :

$$1.6 \times {10^{ - 6}}\Omega m$$

$$1.6 \times {10^{ - 5}}\Omega m$$

$$1.6 \times {10^{ - 8}}\Omega m$$

$$1.6 \times {10^{ - 7}}\Omega m$$

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