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- Question
Working of safety fuses depends upon 1. magnetic effect of the current 2. chemical effect of the current 3. magnitude of the current 4. heating effect of the current Select the correct answer using the code given below.
Options- A. 1, 2, 3 and 4
- B. 1, 2 and 3 only
- C. 3 and 4 only
- D. 4 only
- Correct Answer
- 3 and 4 only
ExplanationAn electric fuse is a device which is used to limit the current in an electric circuit. The fuse safeguards the circuit and the electrical appliances from being damaged.
The fuse wire is generally an alloy of lead and tin. It has a low melting point and breaks the circuit if the current exceeds a safe value. The thickness and length of the fuse wire depends on the maximum current allowed through the circuit.
It is connected in series in the beginning of the electric circuits.
If too many electrical appliances of high power rating (like electric iron, water heater etc) are switched on at the same time, they draw an extremely large current from the circuit. This condition is called overloading and it can cause overheating of the wiring and lead to a fire. (heating effect and magnitude of the current)
- 1. Consider the following statements : 1. There is no net moment on a body which is in equilibrium. 2. The momentum of a body is always conserved. 3. The kinetic energy of an object is always conserved. Which of the statements given above is/are correct?
Options- A. 1, 2 and 3
- B. 2 and 3 only
- C. 1 and 2 only
- D. 1 only Discuss
- 2. Which one of the following is the value of one nanometer?
Options- A. 10-7 cm
- B. 10-6 cm
- C. 10-4 cm
- D. 10-3 cm Discuss
- 3. Sound waves can not travel through a
Options- A. copper wire placed in air
- B. silver slab placed in air
- C. glass prism placed in water
- D. wooden hollow pipe placed in vacuum Discuss
- 4. Addition of suitable impurities into semiconductor, is called
Options- A. Doping
- B. Mixing
- C. Forming
- D. Diluting Discuss
- 5. At what temperature (in Fahrenheit) pure water freezes?
Options- A. 32
- B. 0
- C. 48
- D. 37 Discuss
- 6. Which of the following causes adiabatic temperature changes in atmosphere?
Options- A. Deflection and advection
- B. Latent heat of condensation
- C. Expansion and compression of the air
- D. Partial absorption of solar radiation by the atmosphere Discuss
- 7. Which one of the following is applicable to collision-coalescence process of precipitation?
Options- A. Clouds which do not extend beyond the freezing level
- B. Clouds which extend beyond the freezing level
- C. All types of clouds
- D. Cirrocumulus cloud Discuss
- 8. The bending of light when it passes around a corner or a slit is due to ______.
Options- A. reflection
- B. refraction
- C. diffraction
- D. total internal reflection Discuss
- 9. What is the reason for formation of Mirage in desert?
Options- A. Refraction of light
- B. Reflection of light
- C. Total internal reflection of light
- D. Both Refraction and Total internal reflection of light Discuss
- 10. Two metallic wires made from copper have same length but the radius of wire 1 is half of that of wire 2. The resistance of wire 1 is R. If both the wires are joined together in series, the total resistance becomes
Options- A. 2R
- B. R/2
- C. 5R/4
- D. 3R/4 Discuss
Physics problems
Search Results
Correct Answer: 1 and 2 only
Explanation:
There are two conditions that must be met for an object to be in equilibrium. The first condition is that the net force on the object must be zero for the object to be in equilibrium. If net force is zero, then net force along any direction is zero.
Kinetic energy (KE) is the energy of motion, and kinetic energy is not always conserved in a collision
Energy and momentum are always conserved.
Correct Answer: 10-7 cm
Explanation:
1 nanometer (nm) of length
Equals: 0.00000010 centimetres (cm) in length.
This is equal to 10^-7 cm.
Correct Answer: wooden hollow pipe placed in vacuum
Explanation:
Sound is a kind of energy created when something vibrates. When this vibration reaches an ear, it is translated into what we recognize as a sound. Sound vibration must travel through matter. Therefore, it can travel through air and water but not through vacuum.
Correct Answer: Doping
Correct Answer: 32
Correct Answer: Expansion and compression of the air
Explanation:
Application of temperature changes in the atmosphere is in adiabatics, or temperature change which are caused by compressing or allowing air to expand.
Correct Answer: Clouds which do not extend beyond the freezing level
Explanation:
In colder clouds: droplets formed by Bergeron mechanism. But, in many parts of the world the air is too warm for ice crystals to form. This being the case, rain and snow cannot develop following the Bergeron Process. Instead, tiny droplets form as they collide into one another creating larger and larger droplet, this is known as collision-coalescence process. So, warmer clouds are associated with this keyword.
Correct Answer: diffraction
Correct Answer: Both Refraction and Total internal reflection of light
Correct Answer: 5R/4
Explanation:
So, resistance of Wire 2 is R/4 as radius is half of wire 1, so area would be 4 times of wire 1.
Now for resistance in series. R= R1 + R2.
Therefore, Final R= R + R/4 = 5R/4
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