Science Class 7th
451. The earth pin on plug is ____ than the live and neutral pins, so that it can’t be inserted in live or neutral hole of socket by mistake.
A) Longer
B) Thicker
C) Smaller
D) None
452. Fuse is present in?
A) Three pin plugs
B) Bulb
C) None
453. Which is much more sensitive to current?
A) MCB
B) Fuse
C) None
454. The main purpose of ___ is to prevent injury to humans and animals due to electric shock.
A) MCB
B) ELCB
C) Fuse
455.____ act like electrical circuit in our body.
A) Nerves
B) Blood
C) Oxygen
D) None
456. Humans are good conductors of electricity because of large amount of?
A) Nerves
B) Water
C) Veins
D) Heart
457. A fuse is used to:
A) Prevent electrical flow
B) Save electrical energy
C) Prevent excessive current
D) Increase voltage
458. Sun is a ?
A) Planet
B) Star
C) Comet
D) None
459. The clusters of billions of stars is called?
A) Andromeda
B) Galaxy
C) Universe
460. According to Scientists, most of the universe is?
A) Empty space
B) Full space
C) Filled space
D) None
461. ____ are the building blocks of the universe.
A) Galaxies
B) Stars
C) Moon
D) None
462. Big Bang theory is about?
A) Motion
B) Stars
C) Beginning of Universe
D) None
463. Big Bang theory explains formation of?
A) Planets
B) Stars
C) Galaxies
D) All of these
464. Galaxies are _______ from each other at a great speed in all directions.
A) Moving away
B) Fading away
C) Moving towards
D) None
465. “All the matter in universe was concentrated in ____ micrometer.
A) 2
B) 1
C) 4
D) 5
466. About billions years ago, super dense and hot atom exploded with a big bang.
A) 15
B) 16
C) 20
D) 22
467. Big Bang theory was proposed by?
A) Edwin Hubble
B) Newton
C) Einstein
468. Objects in space that emit light are?
A) Sun
B) Stars
C) Nebulae
D) All of these
469. Objects in space that reflect light?
A) Moon
B) Comets
C) Asteroids
D) All of these
470. Each second 600, 000, 000 tonnes of Hydrogen is converted to ___ in sun.
A) Neon
B) Argon
C) Helium
D) None