Science Class 7th
431. In a circuit, resistance decreases as more resistors are added.
A) Parallel
B) Series
C) None
432. Ohm’s law shows relationship between?
A) Voltage
B) Current
C) Resistance
D) All of these
433.____ is a device used to measure the amount of current an electric circuit.
A) Scale
B) Ammeter
C) Tester
D) None
534. An ammeter has very resistance.
A) High
B) Low
C) None
435. Voltage or potential difference between two points is measured by?
A) Ammeter
B) Scale
C) Voltmeter
D) None
636. Ammeter is connected in ____ in a circuit.
A) Series
B) Parallel
C) None
437. Which of the following has high resistance?
A) Ammeter
B) Voltmeter
C) None of these
438. Which is large unit of energy?
A) Watt
B) Kilowatt hour
C) None
439. ____ is the energy used by a device at a rate of 1000 watts in one hour.
A) Kilowatt hour
B) Watt
C) Both ‘a’ and ‘b’
D) None
440. 1 kWh is equal to Joules.
A) 500000
B) 600000
C) 3600000
441. The main cable through which electricity is supplied to houses contains?
A) Neutral Wire
B) Live Wire
C) Both ‘a’ and ‘b’
D) None
442. A ___ are fitted in the path of live wire.
A) Main wire switch
B) Main circuit breaker
C) Both ‘a’ and ‘b’
D) None
443. To avoid the risk of electric shocks, the metal body of an electrical appliance is?
A) Wired
B) Neutralised
C) Earthed
D) None
444. The wire used in earthing is called?
A) Earth wire
B) Wire
C) Circuit breaker
D) None
445. Thin wire of tin or tin-lead alloy used in fuse has melting point.
A) Low
B) High
C) None
446. Fuse breaks circuit and melts when current exceeds value.
A) Safe
B) Dangerous
C) None
447. Fuse works on the ___ effect of current.
A) Chemical
B) Heating
C) None
448. A fuse wire is connected in to electrical circuit.
A) Series
B) Parallel
449. Which can’t be used as a fuse wire?
A) Tin
B) Tin-lead
C) Copper
D) None
450. Which ensures safe supply of electricity to appliances and reduce chances of electric shocks?
A) Fuse
B) Three pin plugs
C) None