"Science — Moving Things, People and Ideas" — Practice

Question 1

The motion of the tip of a rotating ceiling fan's blade, and the to-and-fro motion of a swinging pendulum, are examples of which two types of motion respectively?
(a) Rectilinear motion; circular motion  (b) Circular motion; periodic (oscillatory) motion  (c) Periodic motion; rectilinear motion  (d) Rectilinear motion; periodic motion

Accepted Answer

The fan blade's tip repeatedly traces a circular path around the fan's axis — circular motion. The pendulum swings to and fro about a fixed mean position at regular time intervals — periodic (oscillatory) motion.

Answer: (b). Trap (a) assigns rectilinear (straight-line) motion to the fan blade, which actually moves along a curved, circular path, not a straight one. Trap (c) swaps the two descriptions entirely. Trap (d) wrongly labels the fan blade's motion as rectilinear and drops the periodic label for the pendulum altogether.

Question 2

A cloth merchant measures a customer's requested length using the span of his own hand, but a different customer, measuring the same cloth with her own hand span, gets a different reading and disputes the length. This scenario most directly illustrates the need for:
(a) A translucent measuring tool  (b) A standard, universally agreed unit of measurement  (c) A circular-motion-based measuring device  (d) A fixed pulley system

Accepted Answer

Hand spans vary from person to person, so the same cloth gives two different readings depending on whose hand measures it — exactly the inconsistency a standard, person-independent unit is designed to remove.

Answer: (b). Trap (a) introduces an unrelated optics term with no bearing on a length-measurement dispute. Trap (c) and trap (d) both invent irrelevant mechanical concepts from other sections of this chapter, neither of which addresses the actual problem of inconsistent, person-dependent units.

Question 3

A nutcracker cracks a nut placed close to its hinge when a person squeezes the two arms together at their far ends. This tool is an example of which class of lever?
(a) Class I, since the hinge (fulcrum) sits between the load and the effort  (b) Class II, since the load (the nut) sits between the fulcrum (the hinge) and the effort (the hands)  (c) Class III, since the effort sits between the fulcrum and the load  (d) Not a lever at all, since a nutcracker has no fixed pivot point

Accepted Answer

The hinge is the fulcrum, the nut (load) sits close to the hinge, and the hands apply effort at the far ends of the arms — the load lies between the fulcrum and the effort, the defining Class II arrangement.

Answer: (b). Trap (a) misplaces the fulcrum's position — in a Class I lever the fulcrum itself sits in the middle, which is not the arrangement described here. Trap (c) misidentifies which term sits in the middle — a Class III lever has the effort, not the load, positioned between the fulcrum and the other end. Trap (d) is factually wrong; the hinge is precisely the nutcracker's fixed pivot point, making it a genuine lever.

Question 4

A fixed pulley mounted at the top of a well lets a person lift a bucket of water by pulling the rope downward instead of hauling it straight up by hand. In terms of mechanical advantage, this fixed pulley:
(a) Reduces the effort needed below the weight of the bucket  (b) Only changes the direction in which the effort is applied, without reducing the effort needed (ideal mechanical advantage of 1)  (c) Doubles the effort needed compared to lifting directly  (d) Eliminates the need for any effort at all

Accepted Answer

A fixed pulley, ignoring friction, has an ideal mechanical advantage of exactly 1 — it changes the direction the effort is applied in (pulling down instead of up) but does not reduce the actual force needed.

Answer: (b). Trap (a) describes the benefit of a MOVABLE pulley (ideal MA = 2), not a fixed one. Trap (c) invents an incorrect penalty with no basis in how a fixed pulley actually behaves. Trap (d) misunderstands machines generally — no simple machine removes the need for effort altogether, it only changes how that effort is applied.

Question 5

During a total solar eclipse, observers standing within the fully dark central part of the Moon's shadow on Earth see the Sun completely blocked, while observers in the surrounding, less-dark ring see only a partial eclipse. The fully dark central region is called the:
(a) Penumbra  (b) Umbra  (c) Corona  (d) Nucleus

Accepted Answer

The fully dark, inner region of a shadow cast by an extended source (the Sun, here effectively blocked by the Moon) is the umbra, where light from every part of the source is blocked.

Answer: (b) Umbra. Trap (a) Penumbra is actually the partially lit, surrounding region described in the question as the 'less-dark ring' — exactly the reverse of what the question asks for. Trap (c) Corona is an unrelated term for the Sun's outer atmosphere, visible during totality but not a shadow region. Trap (d) Nucleus is an unrelated term borrowed from cell biology or atomic structure, with no meaning in shadow formation.

Question 6

A student holds up a card with the word 'AMBULANCE' printed on it in front of a plane mirror. Which property of plane-mirror images explains why the reflected word appears reversed left-to-right?
(a) The image is virtual  (b) The image is laterally inverted  (c) The image is the same size as the object  (d) The image is erect

Accepted Answer

Lateral inversion is specifically the left-right reversal a plane mirror produces, which is exactly why printed text appears mirror-reversed in a reflection — the actual property this question is asking about.

Answer: (b). Trap (a) Virtual correctly describes the image (it cannot be caught on a screen), but this property concerns where the image forms, not why it is left-right reversed. Trap (c) Same size is a true property of plane-mirror images but has nothing to do with the direction of the reversal. Trap (d) Erect describes the image's upright orientation (not upside-down), a separate property from the left-right reversal the question is actually asking about.

Question 7

A Class VI Science textbook chapter opens with a narrative describing how humans moved from walking, to using domesticated animals, to inventing the wheel, to steam trains and aeroplanes — before introducing the concept of standard units of measurement. This opening most directly reflects:
(a) An unnecessary historical digression irrelevant to the science content that follows  (b) NCF 2005's interdisciplinary approach, situating a physics concept (measurement) within the real human history that created the need for it  (c) A social-science lesson mistakenly placed inside a science textbook  (d) A test of students' general-knowledge recall, unconnected to the chapter's actual learning objective

Accepted Answer

NCERT deliberately opens this chapter's physics content with real historical context, connecting the need for standard measurement directly to how human transport and trade actually developed — a genuine, purposeful interdisciplinary teaching choice, not an unrelated aside.

Answer: (b). Trap (a) dismisses a deliberate pedagogical choice as merely incidental filler. Trap (c) wrongly treats the narrative as a misplaced subject, when it is a purposeful bridge built specifically to connect to the measurement content that follows. Trap (d) too narrowly frames the opening as unconnected trivia, ignoring its actual, direct link to the chapter's core learning objective.

Question 8

A student claims, "A lever is useful because it creates extra energy, letting a small push lift a heavy rock that a person alone could never lift." The most accurate correction a Science teacher should give is:
(a) The student is correct; levers generate additional energy through the fulcrum  (b) A lever does not create any extra energy — ignoring friction, the work done by the effort equals the work done on the load; the lever only allows a smaller effort, applied over a larger distance, to move a larger load over a smaller distance  (c) Levers work only because the fulcrum itself supplies extra force  (d) Levers cannot lift loads heavier than the effort applied, regardless of the fulcrum's position

Accepted Answer

A lever redistributes a fixed amount of work between effort and load — a smaller effort moving through a larger distance can move a larger load through a smaller distance — without ever creating new energy; this is the precise, accurate correction of the student's claim.

Answer: (b). Trap (a) directly endorses the student's false claim rather than correcting it. Trap (c) invents an incorrect mechanism — the fulcrum is only a fixed pivot point and supplies no force of its own. Trap (d) is factually wrong; a Class I or Class II lever with the right arm lengths can and routinely does lift a load heavier than the effort applied, which is precisely what mechanical advantage greater than 1 means.

Practice — "Science — Moving Things, People and Ideas"

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