25. while doing an experiment to verify the laws of reflection of sound , in which of the following cases will the sound heard be maximum ?

a. Pipes can either be hollow or solid

b. When one of the pipes is hollow and the other is solid

c. When both the pipes are solid

d. When both the pipes are hollow

26. A student observed the slide of life cycle of a mosquito . the stage prior to the one given will be :

a.adult mosquito egg pupa larva

27. you are given a sphere of radius 2 cm. If you are asked to select a best suited spring balance to determine its weight , then out of the following which one would you prefer / (the sphere is made of an alloy of density 7310³kg m²3.)

I. Range 0 – 1000 gwt , least count 5 gwt

II. Range 0 – 500 gwt , least count 2.5 gwt

III. Range 0 – 250 gwt , least count 2.5 gwt

IV. Range 0 – 100 gwt , least count 1 gwt

28. In an experiment a solid was immersed fully in water and it was observed that the solid has suffered an apparent loss in its weight . This apparent loss in weight of the solid must be equal to the :

I. Weight of the solid in water

II. Weight of the solid in air

III. Weight of water displaced by the solid

IV. Weight of water filled in the vessel

29. If two objects , when immersed in a fluid , have equal up thrust on them , then :

a. Both objects must have equal weights

b. Both objects must have equal volumes

c. Both objects must have equal densities

d. Both objects must have equal mass

30. Reema took a measuring cylinder and filled it with 52ml.of water .She then immersed an object fully in it and noted the water level in the measuring cylinder as 62ml. She found that object appeared lighter when placed in water . the weight loss felt by her is :

10 gwt 52 gwt 62 gwt 104 gwt

31. rinki calculated the pressure exerted by a rectangular block on sand but she forgot the SI units of pressure . The correct units are –

Nm Nm^-1 Nm² Nm^-2

32. The spring balanced used to find the weight of iron block has 20 divisions between the two consecutive readings i.e. 1kg and 2kg. The spring on hanging the weight is stretched to the 4^th division between 4 and 5 on the scale . The weight of the block is :

4.4kg 4.8kg 4.2kg data insufficient

33. the frequency of a vibrating string depends upon :

a. Length of the string

b. Tension in the string

c. Mass per unit length of the string

d. All of these

34. for producing a transverse wave along a slinky ,

a. The free end is jerked at right angle to its length

b. The free end is compressed

c. The free end is pulled

d. None of these

35. out of the following , the organisms having a spiral shaped chloroplast is :

Mushroom spirogyra funeria penicilium

36. shyam has observed following parts in the given slide :

Pyrenoids ribbon like chloroplast filamentous structure

37. The animal whose blood is not the carrier of oxygen to the tissues is :

Toad frog man cockroach

38. cockroaches are able to detect odour with the help of :

Eyes nostrils antennae spiracles

39. while doing an experiment to verify the law of conservation of mass, in a chemical reaction following reaction was performed by yuvraj :

Bacl₂(aq)+Na₂so₄(aq) BaSo₄ g+2NaCl(aq)

208.5g 142g ‘x’g 117g

The correct observation is :

a. 58.5g of BaSo₄ in the form of gas is formed

b. 233.5g white ppt of BaSo₄ is formed

c. 233.5g of black precipitate of BaSo₄ is formed

d. 133.5g of clear solution of BaSo₄ is formed

40. while verifying the law of conservation of mass in a chemical reaction using a precipitation reaction , sachin carried out the following procedure :

I. Determined the mass of white precipitate formed after mixing both the solutions

II. Mixed both solutions in a third beaker , using a glass stirrer .

III. Determined the mass of both solutions separately .

IV. Dissolved the required quantities of BaCl₂ andNa₂So₄ in distilled water

The wrong step in the procedure is :

a) Step (1)

b) Step (2)

c) Step (3)

d) Step (4)

41. four students A,B,C,and D are observing the seeds and flowers of gram plant . They reported their observations that the gram plant has :

A. Dicotyledonous seeds and timorous flowers

B. Dicotyledonous seeds and pentamerous flowers

C. monocotyledonous seeds and timorous flowers

D. monocotyledonous seeds and pentamerous flowers

the student whose report is correct is :

A B C D

42. four students A,B,C,and D are observing the feeding habits of all the developmental stages in the life cycle of mosquito . Their observation that the stage in which it feeds on animal blood is :

Pupa egg larva adult

The correct observation is of student :

A B C D