Best Reference Books for CBSE Class 10 Exam

5) During a trekking activity of 6km a student Ram will go to Sangam and return back up to 12 noon. He estimates that he can go to the Sangam at 1.5km/h on average, and return at half of that speed. These speeds take into account breaks and rest times. Using Ram's estimated speeds, what is the latest time he can begin his walk so that he can return by 12 noon?

A force of F = 70 N is applied on a block of mass M = 10 Kg placed on a horizonatl surface as shown in the figure . What will be the work done by frictional force in t = 2 sec if block was initially at rest

A police jeep on a petrol duty on national highway was moving with a speed of 54km/hr. in the same direction. It finds a thief rushing up in a car at a rate of 126km/hr in the same direction. Police sub – inspector fired at the car of the thief with his service revolver with a muzzle speed of 100m/s. with what speed will the bullet hit the car of thief? CLASS - XI PHYSICS (Kinematics)

(a) State the reasons for which Hershey and Chase carried out their experiments.
(b) Answer the following questions based on the experiments of Hershey and Chase :
(i) Name the different radioactive isotopes they used, and explain how they used them.
(ii) Why did they need to agitate and spin their culture ?
(iii) Write their observations and the conclusions they arrived at.

A student holding a mirror in his hand, directed the reflecting surface of the mirror towards the Sun. He then directed the reflected light on to a sheet of paper held close to the mirror.

(a) What should he do to burn the paper ?

(b) Which type of mirror does he have ?

(c) Will he be able to determine the approximate value of focal length of this mirror from this activity ? Give reason and draw ray diagram to justify your answer in this case. 

A student while observing an embryo of a pen seed in the laboratory listed various parts of the embryo as given below : 

Testa, tegmen, radicle, Plumule, micropyle, cotyledon

On examining the list the teacher remarked that only three parts are correct. Select three correct parts from the above list

a) tests, Radicle, cotyledons    b) Tegmen, Radicle, Microphyle

c) cotyledons, plumule, Testa    d) Radicel, cotyledons, plumule

An amorphous solid “A” burns in air to form a gas “B” which turns lime water milky. The gas is also produced as a by-product during roasting of sulphide ore. This gas decolourises acidified aqueous KMnO4 solution and reduces Fe3+ to Fe2+. Identify the solid “A” and the gas “B” and write the reactions involved.

Describe the structure of seminiferous tubules?? 

Differentiate 2021 with respect yo x

How many of the following points satisfy the inequality 2x-3y≤ -5?

A.  (0, -1)

B. (0, 1)

C. (-4, 0)

D. (4, 0)