Which of the following devices is not used by plants to prevent autogamy

Which of the following devices is used in optocouplers ?

Which of the following devices is used to measure humidity?

Which of the following devices is NOT used to enter data into a computer?

Which of the following devices is // are used for weaving of fabric

In Which of the following devices is a permanent magnet not used ?

Which of the following device is used to remove over 99% particulate matter present in the exhaust from a thermal power plant?

In which of the following devices temporary magnets are used ?

Which of the following devices is used for detecting thermal radiations?