MCQ - CBSE Class 9 Science Two astronauts cannot hear each other on the moon. Why? 10/04/2023 Ajit kumar 106 Views 0 Comments Read more
MCQ - CBSE Class 9 Science Why can we hear echoes in long galleries and big halls? 10/04/2023 Ajit kumar 100 Views 0 Comments Read more
MCQ - CBSE Class 9 Science Explain why echoes can’t be heard in a small room. 10/04/2023 Ajit kumar 107 Views 0 Comments Read more
MCQ - CBSE Class 9 Science Name the waves of frequency greater than 20,000 Hz. Give one use of these waves. 10/04/2023 Ajit kumar 80 Views 0 Comments Read more
MCQ - CBSE Class 9 Science What do you understand by the term ultrasonic vibrations ? 10/03/2023 Ajit kumar 98 Views 0 Comments Read more
MCQ - CBSE Class 9 Science Define the terms: (i) vibration (ii) time period (iii) frequency and (iv) amplitude. 10/03/2023 Ajit kumar 89 Views 0 Comments Read more
MCQ - CBSE Class 9 Science Very Short Answer Type Questions 10/03/2023 Ajit kumar 100 Views 0 Comments Read more
MCQ - CBSE Class 9 Science Explain how the human ear works. 10/03/2023 Ajit kumar 96 Views 0 Comments Read more
MCQ - CBSE Class 9 Science Explain how defects in a metal block can be detected using ultrasound. 10/03/2023 Ajit kumar 98 Views 0 Comments Read more
MCQ - CBSE Class 9 Science How is ultrasound used for cleaning ? 10/03/2023 Ajit kumar 85 Views 0 Comments Read more