CBSE Class 7 Science The Ever-Evolving World of Science (Class 7 NCERT New) Quiz 5

1. Rocks breaking into pebbles and fruits ripening are shown. Which pairing correctly classifies them?

A Both are chemical changes forming new substances B Both are physical changes without new substances C Rocks: chemical change; fruits: physical change D Rocks: physical change; fruits: chemical change

2. Which statement best describes the direction of heat flow between two objects at different temperatures?

A Heat moves equally both directions always B Heat moves from colder to hotter objects C Heat does not move between solid objects D Heat moves from hotter to colder objects

3. Which example matches radiation as shown by the Sun icon in the diagram?

A Boiling water circulating in a pot B Ice melting where salt is sprinkled C Warming hands by a campfire flame D Metal spoon heating where it is held

4. A room is heated when warm air rises and cooler air sinks, forming loops. Which heat transfer method is mainly responsible?

A Radiation from the ceiling B Conduction through the floor C Condensation in the air mass D Convection in the air

5. A sealed metal rod is heated at one end while the other end is cool. After a minute, the temperature at the cool end rises. Which explanation best fits?

A Heat traveled by conduction along the rod B Heat moved by convection inside the solid C Heat radiated only to the surrounding air D Heat created at the cool end spontaneously

6. Heat can cause changes in the state of matter. Which scenario most likely shows this effect of heat flow?

A Salt dissolving faster in cold water B Ice cream melting when placed in warm air C Water level dropping in a closed bottle D A rock changing shape under high pressure

7. An ice cube is left in warm air. Which change is most likely observed?

A Melted into water B Became mouldy C Turned into ash D Produced bubbles

8. When vinegar is mixed with baking soda, what immediate evidence shows a reaction happened?

A Paper turns black B Water freezes solid C Bubbles of gas form D Bread becomes stale

9. Which action is most likely reversible under normal classroom conditions?

A Mixing vinegar with soda B Melting ice into water C Moulding of old bread D Burning paper into ash

10. A puddle disappears on a warm day, later forming clouds and then rain. Which sequence best describes these changes of state?

A Infiltration → Precipitation → Evaporation B Precipitation → Evaporation → Condensation C Condensation → Evaporation → Infiltration D Evaporation → Condensation → Precipitation