Tag: physics

Quizzes (598) Questions (13441)

Questions Related to physics

Multiple choice fluid dynamics option b: engineering physics physics

Vehicles are streamlined to reduce 

  1. Static friction

  2. Kinetic friction

  3. Fluid friction

  4. Slidingfriction
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Fishes have streamlined shape. So, to reduce the fluid friction, the vehicles are made streamlined.

Multiple choice fluid dynamics option b: engineering physics physics

A good lubricant should be highly

  1. viscous and velocity

  2. non-viscous volatile

  3. viscous and non-volatile

  4. transparent
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A good lubricant generally possesses the following characteristics: A high boiling point and low freezing point (in order to stay liquid within a wide range of temperatures) A high viscosity index. Thermal stability.

Multiple choice fluid dynamics option b: engineering physics physics

Two spheres $A$ and $B$ fall through the same viscous fluid. $A$ and $B$ have the same density and $B$ has the larger radius.
Then,

  1. A has the larger terminal velocity

  2. A and B have the same terminal velocity

  3. B has the larger terminal velocity

  4. Insufficient information is given to reach a conclusion.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Two spheres $A$ and $B$ fall through the same viscous fluid $A$ and $B$ have  the same density and $B$ has the larger radius the $B$ has the larger terminal velocity.

$\therefore $ Option $C$ is correct.

Multiple choice fluid dynamics option b: engineering physics physics

Ball pen and fountain pen depends respectively on principle of:-

  1. Surface tension and viscosity

  2. Surface tension and gravity

  3. Gravitation and Surface tension

  4. Surface tension and Surface tension
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ball pens use a ball that rolls ink onto paper, relying on surface tension to keep the ink in the reservoir. Fountain pens rely on capillary action and gravity to feed ink to the nib.

Multiple choice fluid dynamics option b: engineering physics physics

More viscous oil is used in summer than in winter in motors due to

  1. rise in temperature in summer, the viscosity of oil increases.

  2. rise in temperature in summer, the viscosity of oil decreases.

  3. surface tension of oil decreases.

  4. surface tension of oil increases.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Due to rise in temperature viscosity of oil decreases in summers. So more viscous oils are used for better lubricant protection.

Multiple choice fluid dynamics option b: engineering physics physics

With the increasing molecular mass of a liquid, the viscosity .

  1. decreases

  2. increases

  3. no effect

  4. all wrong
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

With the increasing molecular mass of a liquid, the viscosity increases.
The flow of molecules is inversely proportional to its mass. Hence, liquids with high molecular mass possess greater viscosity.

Multiple choice fluid dynamics option b: engineering physics physics

When cooking oil is heated in a frying pan, the oil moves around in the pan more easily when it is hot. The main reason for this is that with rise in temperature, there is a decrease in

  1. density

  2. surface tension

  3. viscosity

  4. angle of contact
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

That is true. The temperature dependence of liquid viscosity is the phenomenon by which liquid viscosity tends to decrease (ore, alternatively, its fluidity tends to increase) as its temperature increase.

Multiple choice ac and dc ac vs dc electro-magnetism effects of electric current physics

The advantage of ac over dc is that:

  1. its generation cost is much less.

  2. it contains more electric energy.

  3. it is free from voltage fluctuations.

  4. it can be transmitted over long distances with minimum power loss.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Answer is B.

The advantage of AC over DC is that power transmission is simpler under AC, it can be changed in voltage relatively easily using transformers, and that higher power motors can be devised under AC. It contains more electric energy.

Multiple choice ac and dc ac vs dc electro-magnetism effects of electric current physics

Transformer is used for

  1. increasing the voltage.

  2. decreasing the voltage.

  3. both A and B

  4. neither A nor B
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In A.C, voltage can be increased or decreased with the help of a transformer. But in D.C, this cannot be done. Voltage may be increased using a step up transformer and may be decreased using a step down transformer.

Multiple choice ac and dc ac vs dc electro-magnetism effects of electric current physics

State whether the following statement is True or False. 

The induced current produced in a closed coil is always direct current. 

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Answer is B.

AC electricity alternates back-and-forth in direction 50 times per second, according to the electrical system in the country. The charge at the ends of the wire alternates between negative (-) and positive (+). If the charge is negative (-), that pushes the negatively charged electrons away from that terminal. If the charge is positive (+), the electrons are attracted in that direction. Thus the electricity in the wire moves in one direction for a short while and then reverses its direction when the generator armature is in a different position. But if the split ring commutators are attached to the coil then the current will move in the same direction.