A thermocouple of negligible resistance produces an e.m.f. of $ 40\, \mu V/^{\circ}C$ in the linear range of temperature. A galvanometer of resistance $10$ ohm whose sensitivity is $1 \, \mu A/division$, is employed with the thermocouple. The smallest value of temperature difference that can be detected by the system will be
- $0.25 ^{\circ} C$
- $0.5 ^{\circ} C$
- $ 1^{\circ} C$
- $0.1^{\circ} C$
The Correct Option is A
Solution and Explanation
$\Rightarrow$ Voltage required $= IR =(1 \,\mu A )(10)=10 \,\mu\, V$
$\therefore 40\, \mu \,V \equiv 1^{\circ} C$
$\Rightarrow 10 \,\mu \,V \equiv \frac{1}{4}{ }^{\circ} C =0.25^{\circ} C$
Top Questions on Current electricity
- A wire has a resistance of \( 10 \, \Omega \) at \( 20^\circ \text{C} \). If the temperature coefficient of resistance of the material is \( 0.004 \, \text{per}^\circ \text{C} \), what is the resistance of the wire at \( 50^\circ \text{C} \)?
- MHT CET - 2025
- Physics
- Current electricity
- The resistance of a wire is \( 10 \, \Omega \) and the current passing through it is \( 2 \, \text{A} \). What is the potential difference across the wire?
- MHT CET - 2025
- Physics
- Current electricity
- A 5-ohm resistor is connected to a 10 V battery. Calculate the current flowing through the resistor.
- MHT CET - 2025
- Physics
- Current electricity
- Two conductors A and B of the same material have their lengths in the ratio 1:2 and radii in the ratio 2:3. If they are connected in parallel across a battery, the ratio \( \frac{v_A}{v_B} \) of the drift velocities of electrons in them will be:
- CBSE CLASS XII - 2025
- Physics
- Current electricity
- A wire of length 2 m and resistance 8 \(\Omega\) is stretched to double its original length, keeping the volume constant. What is the new resistance of the wire?
- MHT CET - 2025
- Physics
- Current electricity
Questions Asked in NEET exam
- A thin flat circular disc of radius 4.5 cm is placed gently over the surface of water. If surface tension of water is 0.07 Nm-1, then the excess force required to take it away from the surface is :
- NEET (UG) - 2024
- Surface tension
- Arrange the following elements in increasing order of first ionization enthalpy:
Li, Be, B, C, N
Choose the correct answer from the options given below:- NEET (UG) - 2024
- Enthalpy change
In a Vernier caliper, \(N+1\) divisions of vernier scale coincide with \(N\) divisions of main scale. If 1 MSD represents 0.1 mm, the vernier constant (in cm) is:
- NEET (UG) - 2024
- Units, Dimensions and Measurements
- In an ecosystem if the Net Primary Productivity (NPP) of first trophic level is 100x (kcal m-2)yr-1, what would be the GPP (Gross Primary Productivity) of the third trophic level of the same ecosystem?
- NEET (UG) - 2024
- Ecosystems
- Two bodies A and B of same mass undergo completely inelastic one dimensional collision. The body A moves with velocity v1 while body B is at rest before collision. The velocity of the system after collision is v2. The ratio v1 : v2 is :
- NEET (UG) - 2024
- Average Velocity and Instantaneous Velocity
Concepts Used:
Current Electricity
Current electricity is defined as the flow of electrons from one section of the circuit to another.
Types of Current Electricity
There are two types of current electricity as follows:
Direct Current
The current electricity whose direction remains the same is known as direct current. Direct current is defined by the constant flow of electrons from a region of high electron density to a region of low electron density. DC is used in many household appliances and applications that involve a battery.
Alternating Current
The current electricity that is bidirectional and keeps changing the direction of the charge flow is known as alternating current. The bi-directionality is caused by a sinusoidally varying current and voltage that reverses directions, creating a periodic back-and-forth motion for the current. The electrical outlets at our homes and industries are supplied with alternating current.