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- Question
Two electric bulbs marked 25W ? 220V and 100W ? 220V are connected in series to a 440Vsupply. Which of the bulbs will fuse?
Options- A. 25 W
- B. Both
- C. 100 W
- D. Neither
- Correct Answer
- 25 W
ExplanationResistances of both the bulbs are
R1=V^2/P1 = 220^2/25
R2 = V^2/P2 = 220^2/100
Hence
When connected in series, the voltages divide in them in the ratio of their resistances. The voltage of 440 V devides in such a way that voltage across 25 w bulb will be more than 220 V. Hence 25 w bulb will fuse.
- 1. Which of the following is not the unit of time
Options- A. Parallactic second
- B. Micro Second
- C. Leap year
- D. Solar day Discuss
- 2. Which of the following is not a vector quantity?
Options- A. speed
- B. velocity
- C. torque
- D. displacement Discuss
- 3. Temperature can be expressed as derived quantity in terms of any of the following
Options- A. length and mass
- B. mass and time
- C. length,mass and time
- D. in terms of none Discuss
- 4. The most suitable unit for expressing nuclear radius is
Options- A. micro
- B. nanometre
- C. fermi
- D. angstrom Discuss
- 5. Nuclear sizes are expressed in a unit named
Options- A. Fermi
- B. Angstrom
- C. Newton
- D. Tesla Discuss
- 6. An air bubble in water will act like a
Options- A. convex lens
- B. convex mirror
- C. concave lens
- D. concave mirror Discuss
- 7. If a sound travels from air to water, the quantity that remain unchanged is
Options- A. velocity
- B. frequency
- C. wavelength
- D. amplitude Discuss
- 8. Rain drops acquire spherical shape due to
Options- A. viscosity
- B. surface tension
- C. friction
- D. elasticity Discuss
- 9. When a bottle of perfume is opened in one corner of a room the smell spreads soon throughout the room. This is an example of
Options- A. surface tension
- B. capillarity
- C. viscosity
- D. diffusion Discuss
- 10. It is more difficult to walk on ice than on a concrete road because
Options- A. there is very little friction between the ice and feet pressing it
- B. ice is soft when compared to concrete
- C. there is more friction between the ice and feer
- D. None of these Discuss
Physics problems
Search Results
Correct Answer: Parallactic second
Correct Answer: speed
Correct Answer: in terms of none
Correct Answer: fermi
Correct Answer: Fermi
Explanation:
Nuclear sizes are expressed in a unit called "Fermi" which is a unit of length equal to 10?15 metre (one femtometre), used in nuclear physics. It is similar to the diameter of a proton.
Correct Answer: concave lens
Correct Answer: frequency
Correct Answer: surface tension
Correct Answer: diffusion
Explanation:
Diffusion is the spreading - mixing of gases through molecular motion.
Correct Answer: there is very little friction between the ice and feet pressing it
Explanation:
It is the friction between the feet and the ground that helps us to walk. Without this friction we would slip and fall
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