Look at the given figure. Will there be any difference in the shadow formed on the screen in A and B?
The same shadow will be formed on screen A and B because formation of the image depends on the size... View Article
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Three torches A, B and C shown in the figure are switched on one by one. The light from which of the torches will not form a shadow of the ball on the screen.
Torch A and B are placed in front of the screen so they will form image. As torch C is... View Article
Observe the picture given in figure A sheet of some material is placed at position ‘P’, still the patch of light is obtained on the screen. What is the type of material of this sheet?
P is the sheet of some transparent material like thin plastic, ground glass etc. Because only the transparent materials allows... View Article
You have 3 opaque strips with very small holes of different shapes as shown in the figure. If you obtain an image of the sun on a wall through these holes, will the image formed by these holes be the same or different?
All three objects will form the same kind of image of the sun irrespective of their shapes as the holes... View Article
Two students while sitting across a table looked down on to its top surface. They noticed that they could see their own and each other’s image. The table top is likely to be made of (a) Unpolished wood (b) Red stone (c) Glass sheet (d) Wood top covered with cloth
c) Glass sheet Explanation All the other objects are opaque and non-reflecting in nature. And a glass sheet is transparent.... View Article
Which of the following can never form a circular shadow? (a) A ball (b) A flat disc (c) A shoe box (d) An ice cream cone
c) A shoebox Explanation For forming the circular shadow the object should have a circular shape. A shadow is formed... View Article
Paheli observed the shadow of a tree at 8:00 a.m., 12:00 noon and 3:00 p.m. Which of the following statements is closest to her observation about the shape and size of the shadow? (a) The shape of the shadow of the tree changes but the size remains the same. (b) The size of the shadow of the tree changes but the shape remains the same. (c) Both the size and shape of the shadow of the tree change. (d) Neither the shape nor the size of the shadow changes.
c) Both the size and shape of the shadow of the tree change Explanation With the change in the time the... View Article
Which of the following is/are not always necessary to observe a shadow? (a) Sun (b) Screen (c) Source of light (d) Opaque object
a) Sun Explanation Shadow can be formed from other sources of light also, like, torch. A shadow is actually just a... View Article
Four students A, B, C and D looked through pipes of different shapes to see a candle flame as shown in the figure. Who will be able to see the candle flame clearly? (a) A (b) B (c) C (d) D
d) D. Explanation The tube is straight in fig D. Therefore, candle flame will be visible clearly to us. The... View Article
A student observes a tree given in figure through a pinhole camera. Which of the diagrams given in figures (a) to (d) depicts the image seen by her correctly?
The image formed by pinhole camera is inverted and left – right reversed. Option (a) : the image is not... View Article
Observe the picture given in figure carefully. A patch of light is obtained at B, when the torch is lighted as shown. Which of the following is kept at position A to get this patch of light? (b) A glass sheet (c) A mirror (d) A sheet of white paper,
Answer is (c) Mirror Explanation A mirror is kept at position A to get a patch of light because only... View Article
Boojho was riding in his bicycle along a straight road. He classified the motion of various parts of the bicycle as (i) rectilinear motion (ii) circular motion and (iii) both rectilinear as well as circular motion. Can you list one part of the bicycle for each type of motion? Support your answer with reason.
Type of Motion Part of bicycle Reason Rectilinear Handles The handles do not move in circular or rotatory motion. Circular... View Article
Three students measured the length of a corridor and reported their measurements. The values of their measurements were different. What could be the reason for difference in their measurements? (Mention any three)
Reasons for different measurement could be- (i) Defective instrument or are not standardised. (ii) Wrong method of measurement. (iii) Use... View Article
How are the motions of a wheel of a moving bicycle and a mark on the blade of a moving electric fan different? Explain.
Wheels of a moving bicycle show rectilinear motion and circular motion. Because when the wheel is rotating, it also moves... View Article
While travelling in a train, it appears that the trees near the track are moving whereas co-passengers appear to be stationary. Explain the reason.
The trees appear to be in moving opposite direction while travelling in a train because the position of trees is... View Article
Four children measure the length of a table which was about 2m. Each of them used different ways to measure it. (i) Sam measured it with a half metre long thread. (ii) With a 15cm scale from her geometry box. (iii) Reena measured it using her hand span. (iv) Salim measured it using a 5m long measuring tape. Which one of them would get the most accurate length? Give reason for your answer.
(iv) Salim measured it using a 5m long measuring tape. Explanation The most accurate measurement will be done by Salim... View Article
The photograph given in figure shows a section of a grille made up of straight and curved iron bars. How would you measure the length of the bars of this section, so that the payment could be made to the contractor?
It is quite visible in the figure, the grille is made up of two types of iron bars, straight and... View Article
Write one example for each of the following type of motion. (i) Rectilinear (ii) Circular (iii) Periodic (iv) Circular and periodic
(i) Rectilinear motion – A car moving in straight line. An object is said to be in a rectilinear motion... View Article
Fill in the blanks. (i) Motion of an object or a part of it around a fixed point is known as_______ motion. (ii) A body repeating its motion after certain interval of time is in_______ motion. (iii) In rectilinear motion, object moves a______ line______. (iv) SI unit of length is_______.
(i) Motion of an object or a part of it around a fixed point is known as circular motion. Circular... View Article
Correct the following: (i) The motion of a swing is an example of rectilinear motion. (ii) 1m = 1000cm
(a) The motion of a swing is an example of periodic motion. motion that repeats itself after equal intervals of... View Article
