Daily Quiz

EXPLANATION:

Radioactive decay is a nuclear process, meaning it happens deep inside the atom’s nucleus. It is spontaneous and random, so it does not require external energy (like heat) to occur. Because the nucleus is tiny and well-shielded, external conditions like temperature or pressure cannot reach it to change how fast it decays.

Why other answers are wrong: Incorrect choices often apply to chemical reactions. In chemistry, increasing temperature makes atoms collide more often, speeding up the reaction. However, nuclear decay happens from within a single atom and does not depend on collisions or electron interactions.

Helpful Tip: Think of chemistry as dealing with the "skin" (electrons) of the atom and radioactivity as dealing with the "heart" (nucleus). While heat can easily affect the "skin," the "heart" remains untouched by outside changes!

EXPLANATION:

When water reaches its boiling point (373 K), it undergoes a phase change.

Why D is correct: During boiling, the temperature remains constant even though thermal energy is being added. This energy doesn't make the molecules move faster (which would raise the temperature); instead, it is used to break the attractive bonds between molecules to turn liquid into gas. This increases the internal potential energy, not the kinetic energy.

Why others are incorrect:

• Temperature rise: Any answer suggesting the temperature increases is incorrect because boiling occurs at a fixed temperature plateau.
• Kinetic energy: Since temperature is a measure of average kinetic energy, if the temperature is constant, the kinetic energy must also remain constant.

Helpful Tip: Energy has two "jobs": it can either change the speed of particles (Temperature/Kinetic Energy) OR their bond strength/spacing (Phase/Potential Energy). They never happen at the same time!

EXPLANATION:

On a speed-time graph, the vertical axis (y-axis) shows how fast an object is going. A horizontal line means that as time passes, the speed value stays exactly the same. Since the speed isn't changing, the object is moving at a constant speed.

Why other answers are wrong:

• Object at rest: If the object were stopped, the line would be flat on the time axis (speed = 0).
• Changing speed (Acceleration/Deceleration): If the speed were increasing or decreasing, the line would slant upwards or downwards.

Helpful Tip: Always check the axis labels! On a distance-time graph, a horizontal line means the object has stopped. But on a speed-time graph, a horizontal line means it is moving at a steady pace. Don't mix them up!

To understand resistance, think of the formula: Resistance = (Resistivity × Length) / Area.

Why D is correct: Resistance depends on two factors here:

1. Length: Wire Y is twice as long ($2L$), which doubles its resistance.
2. Area: Wire Y has twice the area ($2A$), which halves its resistance.

Because these two changes cancel each other out ($2 ÷ 2 = 1$), the resistance remains exactly the same as wire X.

Why other answers are incorrect: Any answer claiming one wire has more resistance than the other is incorrect because it only focuses on one change. If you only consider length, Y seems higher; if you only consider area, Y seems lower. You must combine both!

Helpful Tip: Think of a highway. If you make the road twice as long (more traffic), but also add twice as many lanes (more space), the "difficulty" of driving through stays the same!

When white light enters a prism, it splits into a rainbow because different colors of light travel at different speeds inside the glass.

Why Red is Correct: Red light has the longest wavelength and the highest speed in the glass. Because it stays faster than the other colors, it doesn't "trip" or slow down as much. This means it undergoes the smallest change in direction, so it is refracted (bent) the least.

Why Others are Incorrect: Colors like orange, green, and blue have shorter wavelengths than red, so they slow down more and bend further. Violet has the shortest wavelength and slows down the most, meaning it is refracted the most.

Helpful Tip: Remember the acronym ROYGBIV. The colors are always listed from least bent (Red) to most bent (Violet). Just remember: Red stays ahead because it’s the fastest!