All Free Everyday Science MCQs with Answers

1571. The spray bottles used as window or household cleaner or perfume spray works on: __________?

• A. Capillary action
• B. Bernoulli's Principle
• C. Pascal's Law
• D. Stoke's Law

Explanation: In a spray bottle, rapidly moving air lowers pressure above the liquid, allowing atmospheric pressure to push the liquid up the tube and disperse it. This is an application of Bernoulli's principle.

1572. What is unit of Pressure?

• A. Barr
• B. Torr
• C. Pascal
• D. All of these

Explanation: The pascal is the SI unit of pressure, while the torr and bar are also accepted pressure units. Thus, “Barr” is presumably a misspelling of bar, making all the listed units valid.

1573. Triple point of water is _________?

• A. 271 K
• B. 272.2 K
• C. 273.16 K
• D. None of these

Explanation: Water’s triple point, where ice, liquid water and water vapour coexist in equilibrium, is defined as 273.16 K. This is slightly above the ordinary ice point of about 273.15 K.

1574. Stars in the sky appear to twinkle due to _________?

• A. a series of refractions
• B. a series of reflections
• C. a surface tension phenomenon
• D. multiple diminishing brightness

Explanation: Starlight passes through turbulent layers of Earth’s atmosphere, where repeated refraction changes its apparent direction and brightness. Nearby planets usually twinkle less because their visible discs average out these fluctuations.

1575. A bird sitting on a high tension electric wire does not get electrocuted because:

• A. Sit has high resistance
• B. the body is earthed
• C. it does not form a closed path for the flow of current
• D. its feet are good insulators

Explanation: A bird on a single wire has both feet nearly at the same electrical potential, so there is no significant voltage across its body to drive current. Merely touching a high-voltage wire is dangerous when another contact provides a potential difference.

1576. 1 tonne = _____ kg?

• A. 100
• B. 400
• C. 1000
• D. 4000

Explanation: A tonne, also called a metric ton, is equal to 1,000 kilograms. This is distinct from some historical or regional ton units, whose masses differ slightly.

1577. A photostat machine works on _____________?

• A. electromagnetic image making
• B. magnetic image making
• C. thermal image making
• D. electrostatic image making

Explanation: A photostat machine gives the document and drum electrostatic charges, so toner sticks selectively to form the copy. This is why its basic principle is called electrostatic image making.

1578. The snow on the mountains does NOT melt all at once when it is heated by the sun because:

• A. it becomes very hard
• B. it reflects most of the heat from the sun
• C. it has a low specific heat capacity
• D. it has a high latent heat of fusion

Explanation: Ice requires a large amount of latent heat of fusion to change into water without a temperature rise. Therefore, even under sunlight, mountain snow melts gradually rather than all at once.

1579. Which of the following statements is true when we see 'rainbow' ?

• A. We face sun and raindrops
• B. The Sun remains behind us and we face raindrops
• C. In light rainfall, we face Sun
• D. The sky remains clear and the sun is at lower position in the sky

Explanation: A rainbow appears when sunlight is behind the observer and raindrops are in front, because the drops disperse, refract, and internally reflect the light toward the observer. Facing the Sun places the rainbow generally behind the observer.

1580. Rain drops fall from great height Which among the following statements is true regarding it?

• A. they fall with that ultimate velocity, which are different for different droplets
• B. they fall with same ultimate velocity
• C. their velocity increases and they fall with different velocity on the earth
• D. their velocity increases and they fall with same velocity on the earth

Explanation: Raindrops quickly reach terminal velocity when air resistance balances their weight. The terminal speed differs with droplet size, so different-sized drops do not all fall at the same speed.