Q) The angles of depression of the top and the bottom of a 50 m high building from the top of a tower are 45° and 60°, respectively. Find the height of the tower. (Use √3 = 1·73) Ans: Let’s start with the diagram for this question: Here we have tower AB is the tower […]
The angles of depression of the top and the bottom of a 50 m high building from the Read More »
Q) Rehana went to a bank to withdraw Rs. 2,000. She asked the cashier to give her Rs. 50 and Rs. 100 notes only. Rehana got 25 notes in all. Find how many notes of Rs. 50 and Rs. 100 did she receive. Ans:Â Let’s consider Notes of Rs. 50 = X and Notes of
Rehana went to a bank to withdraw Rs. 2,000. She asked the cashier to give her Read More »
Q) The above circuit is a part of an electrical device. Use the information given in the question to calculate the following: (i) Potential Difference across R2. (ii) Value of the resistance R2. (iii) Value of resistance R1 (CBSE Sample Paper – 2024-25) Ans:Â STEP BY STEP SOLUTION (i) Potential Difference across R2 : Since
The above circuit is a part of an electrical device. Use the information given Read More »
Q) Two resistors of resistances 2 Ω and 4 Ω are connected in a) series b) parallel with a battery of given potential difference. Compute the ratio of total quantity of heat produced in the combination in the two cases if the total voltage and time are kept the same for both. (CBSE Sample Paper –
Two resistors of resistances 2 Ω and 4 Ω are connected in Read More »
Q) As shown in the figure above A and B are two lamps. Lamp A is rated at 12 V,24W. Lamp B is rated at 6.0 V. When lamp B operates at its rated voltage, the current in it is 3.0 A. The values of R1 and R2 are chosen so that both lamps operate
As shown in the figure above A and B are two lamps. Lamp A is rated at 12 V,24W. Read More »
Q) In a household five fans each of 100W are used for 4 hours and an electric press of 500W for 2 hours every day. Calculate the cost of using the fans and electric press for 60 days if the cost of 1 unit of electrical energy is Rs. 6.5.   (CBSE Sample Paper
In a household five fans each of 100W are used for 4 hours and an electric press Read More »
Q) Two pillars of equal lengths stand on either side of a road which is 100 m wide, exactly opposite to each other. At a point on the road between the pillars, the angles of elevation of the tops of the pillars are 60° and 30°. Find the length of each pillar and distance of
Two pillars of equal lengths stand on either side of a road which is 100 m wide Read More »
Q) A train travels a distance of 90 km at a constant speed. Had the speed been 15 km/h more, it would have taken 30 minutes less for the journey. Find the original speed of the train. Ans: Let’s consider the speed of the train is XÂ km/hr. Now, to cover distance of 90 km, it
Q) A man on a cliff observes a boat at an angle of depression of 30° which is approaching the shore to the point immediately beneath the observer with a uniform speed. Six minutes later, the angle of depression of the boat is found to be 60°. Find the time taken by the boat from
A man on a cliff observes a boat at an angle of depression of 30° which is approaching Read More »
Q) The angle of elevation of a jet plane from a point A on the ground is 60°. After a flight of 30 seconds, the angle of elevation changes to 30°. If the jet plane is flying at a constant height of 3600 √3 m, find the speed of the jet plane. Ans: Let’s start