ANS:E - Universe

Explanation: All except Universe form a part of the universe.

ANS:B - used once

Primary batteries (disposable batteries), which are designed to be used once and discarded when they are exhausted. Secondary batteries (rechargeable batteries), which are designed to be recharged and used multiple times.

ANS:A - Both A and R are true and R is the correct explanation of A

Both Assertion (A) and Reason (R) are true, but R is not a correct explanation of A. Assertion (A) is true because the determination of pH value in sewage is indeed important. pH value affects the solubility, chemical reactions, and microbial activity in sewage, which in turn influence the efficiency of treatment processes and the overall performance of sewage treatment plants. Reason (R) is true because the efficiency of certain treatment methods, such as biological treatment processes, chemical precipitation, and disinfection, can be significantly influenced by the pH value of sewage. For example, in biological treatment processes, pH affects the activity and growth of microorganisms responsible for organic matter degradation. Similarly, in chemical precipitation, pH influences the precipitation of metals and other contaminants. However, while Reason (R) correctly identifies that the efficiency of certain treatment methods depends on the availability of pH value, it does not directly explain why the determination of pH value is important. The importance of pH value in sewage goes beyond just treatment efficiency; it also affects the overall performance and operation of sewage treatment systems. Therefore, R is not a correct explanation of A. So, the correct option is: Both A and R are true but R is not a correct explanation of A.

ANS:A - 0.833 kHz

Mod-12 counter is divide by 12 counter. Output frequency = = 0.833 kHz.